msm_fb: Add support for "Continuous Splash Screen" on 8x25 EVB

Add changes to support continuous splash screen on 8x25
for video and command mode panels. Delay the MDP hardware
initialisation, keep video timing generator enable during boot up,
do not disturb the GPIO/regulator configurations and skip the
panel initialization sequence during boot up.

Change-Id: Id5e635ca986e66abb3cbf7c5a174f952ea489708
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>