Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Clean some 'svn:executable' properties in the tree.

Submitted by: Christoph Mallon
MFC after: 3 days

Remove explicit CC assignment in isci(4) Makefile to allow for building
with clang. Also fix a number of warnings uncovered when building with
clang around some implicit enum conversions.

Sponsored by: Intel
Approved by: scottl

Fix r231134. svn:keywords needs to be 'FreeBSD=%H', not 'FreeBSD:%H'.

Approved by: scottl

Add svn:keywords for isci driver files.

Sponsored by: Intel
Approved by: scottl

Add isci(4) driver for amd64 and i386 targets.

The isci driver is for the integrated SAS controller in the Intel C600
(Patsburg) chipset. Source files in sys/dev/isci directory are
FreeBSD-specific, and sys/dev/isci/scil subdirectory contains
an OS-agnostic library (SCIL) published by Intel to control the SAS
controller. This library is used primarily as-is in this driver, with
some post-processing to better integrate into the kernel build
environment.

isci.4 and a README in the sys/dev/isci directory contain a few
additional details.

This driver is only built for amd64 and i386 targets.

Sponsored by: Intel
Reviewed by: scottl
Approved by: scottl

Add man page and update a few other files in preparation for committing full isci driver.

Sponsored by: Intel
Reviewed by: scottl

Modify GENERIC, files and options for isci (Intel C600 SAS controller) driver.
Also add brief README and cleanup Makefile.

Reviewed by: scottl sbruno

Add initial version of Makefile for isci driver.

Approved by: scottl
Obtained from: Intel