CHROMIUM: staging/vxd392: Add BYT Media Driver

This driver is separate from i915 as it controls
the VED media block in BYT.  However, VED shares
the same PCI ID as the GUNIT and so hangs off of
it.

Due to the GUNIT and VED interface, it require some
modifications to the i915.  A subsequent commit will
provide the hooks in i915 for VED support.

The VED has a single power island on BYT.  It has
a power enable signal controlled by PUNIT, and has
output firewalls, with the firewall enable signal
controlled by PUNIT.  It is currently handled through
private msgbus but plan to clean up with intel-mid
support.

The module is enabled via CONFIG_DRM_VXD_BYT.

BUG=chrome-os-partner:25502
TEST=Apply this patch and subsequent i915 integration
patch.  Build x8_64 with CONFIG_DRM_VXD_BYT enabled,
boot and modprobe vxd392 without errors.

Change-Id: I407ba8df920f9c323d5fc8d3fff8dee89e780aae
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
CHROMIUM: i915: Integrate BYT Media Driver

Due to the GUNIT handling of the VED Media
block in BYT, hooks must be added to
provide an interface for the VXD392
driver.

BUG=chrome-os-partner:25502
TEST=Apply associated BYT Media Driver patch in addition
to this patch.   Build x8_64 with CONFIG_DRM_VXD_BYT enabled,
boot and modprobe vxd392 without errors.

Change-Id: I40a4817fb60d0dbad644dbe720600bb59b55da31
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>