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

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

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

pmap_unmapdev/bios: Accept a pointer instead of a vm_offset_t.

This matches the return type of pmap_mapdev/bios.

Reviewed by: kib, markj
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D36548

xen: Remove unused devclass arguments to DRIVER_MODULE.

xen: Use devclass_find to lookup devclasses in identify.

While here, use driver->name instead of hardcoding the xenpv and
xen_et strings both for devclass_find() and BUS_ADD_CHILD().

Reviewed by: Elliott Mitchell <ehem+freebsd@m5p.com>, imp, royger
Differential Revision: https://reviews.freebsd.org/D35001

xen: use correct cache attributes for Xen specific memory regions

bus_activate_resource maps memory regions as uncacheable on x86, which
is more strict than required for regions allocated using xenmem_alloc,
so don't rely on bus_activate_resource and instead map the region
using pmap_mapdev_attr and VM_MEMATTR_XEN as the cache attribute.

Sponsored by: Citrix Systems R&D

xen/xenpv: remove low memory limit for non-x86

For embedded devices reserved addresses will be known in advance. More
recently added devices will also likely be correctly updated. As a
result using any available address is reasonable on non-x86.

Reviewed by: royger
Differential Revision: https://reviews.freebsd.org/D29304

xen: create VM_MEMATTR_XEN for Xen memory mappings

The requirements for pages shared with Xen/other VMs may vary from
architecture to architecture. As such create a macro which various
architectures can use.

Remove a use of PAT_WRITE_BACK in xenstore.c. This is a x86-ism which
shouldn't have been present in a common area.

Original idea: Julien Grall <julien@xen.org>, 2014-01-14 06:44:08
Approach suggested by: royger
Reviewed by: royger, mhorne
Differential Revision: https://reviews.freebsd.org/D29351

xen: move x86/xen/xenpv.c to dev/xen/bus/xenpv.c

Minor changes are necessary to make this processor-independent, but
moving the file out of x86 and into common is the first step (so
others don't add /more/ x86-isms).

Submitted by: Elliott Mitchell <ehem+freebsd@m5p.com>
Reviewed by: royger
Differential Revision: https://reviews.freebsd.org/D29042