msm: mdss: separate out DBA and CEC functionality from DSI

Currently, DBA (Display Bridge Abstract) related functionality
is being used in DSI files. Carve out DBA related functionality
into a new file which serves as a utility module and can be used
by any MDSS driver.

Define CEC on/enable functions in DBA (Display Bridge Abstract) so that
clients can enable disable CEC based on other dependent CEC modules.
Separate out CEC abstract data with CEC driver data and initialize and
release corresponding modules properly.

Change-Id: I84f53d99547dcd4ce0b8275401b03ed8e96e14d5
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>