davinci: fb: fix frame buffer driver issues

Following issues have been addressed on DA8XX/OMAP-L1XX:

a. Screen misalignment during booting when frame buffer console is
   enabled.

b. Driver was configured always in PSEUDOCOLOR mode.  This patch
   dynamically configures the driver either in PSEUDOCOLOUR or TRUECOLOR
   mode depending on bpp.

c. The RED and BLUE offsets were interchanged resulting in wrong
   bootup logo colour.

This patch has been tested on DA830/OMAP-L137 and DA850/OMAP-L138 EVMs.

Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Cc: Steve Chen <schen@mvista.com>
Cc: Pavel Kiryukhin <pkiryukhin@ru.mvista.com>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>