Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

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

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

drm: Const'ify the 1st "drm_display_mode" passed to "mode_fixup" callbacks

This will be needed by the Radeon KMS driver.

drm and i915: Left-shift iic_msg.slave at creation time

This is required because, in the radeon driver, we can't left-shift in a
central place, like it was done in the i915 driver.

Reviewed by: kib@, kan@, avg@
Tested by: kib@, avg@

Add the code for new Intel GPU driver, which supports GEM, KMS and
works with new generations of GPUs (IronLake, SandyBridge and
supposedly IvyBridge).

The driver is not connected to the build yet.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week