drm/msm: use sde specific color format throughout

Move sde_kms to register its own color format structure for get_format
to consolidate all format definitions. Also, make sde_format structure
compatible with mdp_format by having a common msm_format base.

Change-Id: I79bd4e84633618865456c0d21bcace67c3c8cb80
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>