drm/msm/sde: explicitly enumerate supported plane formats

Explicitly list supported formats rather than attempting to
infer what is supported based on h/w features. This makes
the determination of supported formats more reliable, and
also opens the way to account for different h/w blocks
supporting different sets of formats.

Change-Id: I39b223638c2c126d57eee5551a57c7b8fd7cb1f5
Signed-off-by: Clarence Ip <cip@codeaurora.org>