drm/msm: add generic property/state handling

Add generic atomic properties and private state structure
handling. The 'msm_property' class of helper functions capture
common code for storing local property values, handling atomic
state/property callbacks and basic blob property management.

Change-Id: I5be2d9c45d21c9d50e340036fdd7638e6b8c7ab9
Signed-off-by: Clarence Ip <cip@codeaurora.org>