OMAPDSS: DSSCOMP: efficiency improvement.

This change adds 3 local caches of objects, which are used at each flip buffer
action. In original variant kzalloc()/kfree() functions are called each time
dsscomp_gralloc_queue() function is called. This meens that slab|slob|slub
common cache is used at each frame draw action. Call to kzalloc()/kfree()
result in synchronization with other code, which uses common cache, and can
result in dips in FPS, when other code allocates/frees memory.
This change improves reliability, autonomy and efficiency of DSSCOMP module.

Change-Id: Id50778f4579309fb71318a32820b9d6441a6dac1
Signed-off-by: Mykhailo Denysiuk <x0172934@ti.com>

Conflicts:
	drivers/video/omap2/dsscomp/gralloc.c
	drivers/video/omap2/dsscomp/queue.c