davinci: fb : add suspend/resume suuport for DA8xx/OMAP-L1xx fb driver

Suspend/resume support DA8xx/OMAP-L1xx frame buffer driver.  This feature
has been tested on DA850/OMAP-L138 EVM.  For the purpose of testing, the
patch series[1] which adds suspend support for DA850/OMAP-L138 SoC was
applied.

[1] http://patchwork.kernel.org/patch/60260/



Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>