msm: kgsl: Add caching support for DRM GEM allocations

This change adds 3 KGSL DRM ioctls:

DRM_IOCTL_KGSL_GEM_SET_USERDATA
DRM_IOCTL_KGSL_GEM_SET_USERDATA
DRM_IOCTL_KGSL_GEM_CACHE_OPS

Get and set userdata ioctls are used by userspace to
store information like last operation (Read/Write) done
on this DRM object and last mapping (CPU/GPU) done for
this DRM object. This is required to optimize number of
cache operations on DRM GEM objects.

DRM_IOCTL_KGSL_GEM_CACHE_OPS is used by userspace to
perform cache operations on DRM GEM objects.

Change-Id: Id228a52da90cafed6a2b9e0b000117ad7aa8e366
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>