drm/msm: Fix fbdev for 16- and 24-bit modes.

drm/msm: Fix fbdev for 16- and 24-bit modes.

Currently forcing the video mode from the kernel command line (for example
video=HDMI-A-1:1280x720-16@60) does not correctly set the number of bits
per pixel. This is due to a rather aggressive override in
msm_fbdev_create(). This is a particular problem for Android bring up
because the software EGL fallbacks don't support 32bpp.

Since the overrides are actually the default values anyway then this
problem can be trivially fixed by removing the overrides completely.

Change was tested by dd'ing a test image to /dev/fb0 with no video=
(still 32bpp), video=1920x1080-32@60, video=1920x1080-24@60 and
video=1920x1080-16@60 .

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Rob Clark <robdclark@gmail.com>