intrng: Allow alternative IPI PICs to be registered and used

On RISC-V, the root PIC (whether the PLIC or, as will be the case in
future, the local interrupt controller) cannot send IPIs, relying on
another means to trigger the necessary software interrupts (firmware
calls), but there are upcoming standard devices that will be able to
inject them, so we can't just put the firmware calls in the root PIC
driver.

Thus, split out a new intr_ipi_dev from intr_irq_root_dev to use for
sending IPIs. New devices can be registered with a given priority up
until the first IPI is set up, when the best device seen so far gets
frozen as the IPI device to use.

Reviewed by: mhorne
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D35899

intrng: Remove irq_root_ipicount and corresponding intr_pic_claim_root arg

The static irq_root_ipicount variable is only ever written to (with the
value passed to irq_root_ipicount), never read. Moreover, the bcm2836
driver, as used by the Raspberry Pi 2B and 3A/B (but not 4, which uses a
GIC-400, though does have the legacy interrupt controller present too)
passes 0 as ipicount, despite implementing IPIs. It's thus inaccurate
and serves no purpose, so should be removed.

Reviewed by: mmel, imp, mhorne
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D35897

sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

gic_acpi: Limit the number of CPUs to GIC_MAXCPU

madt_table_data contains an array of pointers for each CPU and was
allocated on the stack. If MAXCPU is raised to a sufficiently large
value this can overflow the kernel stack. Cap the stack growth by
using GIC_MAXCPU instead as for other parts of the gicv1/v2 driver in
commit a0e20c0ded1a.

Suggested by: andrew
Reviewed by: andrew, emaste
Obtained from: CheriBSD
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D41800

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

arm/arm: Remove unused devclass arguments to DRIVER_MODULE.

Add missing ACPI GICv2 MSI/MSI-X attachment

This lets PCIe MSI-X device interrupts work on the MACCHIATObin
(Marvell Armada 8k), which allows e.g. the Intel igb NIC to fully work.

Submitted by: Greg V <greg@unrelenting.technology>
Reviewed by: mw, bcran
Differential Revision: https://reviews.freebsd.org/D20775

Fix the GIC ACPI cross reference value.

To support INTRNG with ACPI we need to set a non-zero cross reference value
for the interrupt controller. The GICv3 driver already had this value set,
however it was missed in the GICv2 driver. Fix this by setting xref to the
correct value.

Approved by: re (gjb)

Add the missing header for malloc(9). It was pulled in through header
pollution that doesn't seem to exist in some configurations.

Rename the ACPI variant of the gicv2m driver from "gicv2m" to "gicv2m_acpi".
The FDT variant is called "gicv2m" too, and as both would try to register
on gic, only one of them would succeed, while we want them both in a
GENERIC kernel.

Reviewed by: andrew

iAdd ACPI attachments the the GIC and GICv3 interrupt controller drivers.
For each we need to walk the MADT to find which we have, then add the
driver as needed. As each may have a child they will each walk the same
table to find these details.

Reviewed by: mmel
Obtained from: ABT Systems Ltd
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D8720