OMAPDSS: drop small YUV encoded frames on OMAP44xx

OMAP44xx has hardware limitation: in stall mode, when the frame pixel size
is less than output SyncFifo depth(16), DISPC hangs without sending any data.
Simple workaround is to drop such frame, as cases when YUV frames of this size
are very rare.

Change-Id: I31dc262b07a52b66209c093f136ad2bac66f9439
Signed-off-by: Sergiy Kibrik <sergiy.kibrik@globallogic.com>