msm: vidc: Add debug support for video driver

Add debugfs and other debug support for video
codec driver. This creates a debugfs entry
on device for video and basic information
about video playback and encoding can be obtained
from the debugfs files.

Change-Id: Id4d3d7f6e38bb4993587621ecb8e5dc6bbeb00fd
Signed-off-by: Vinay Kalia <vkalia@codeaurora.org>