gcbv-user: validate dest rect after clipping
gcbv-user: validate dest rect after clipping

According to bltsville spec, rectangles should not be checked
for validity until clipping has been applied.  So we must clip
the dest rect before validating it.  Removed the error checking
from the generic rect converter macro.  Added error checking
specifically for clip rect and dest rect, post clipping. Proper
validity checking of other rects is TBD.

Change-Id: I07022b5d112bf7b25f592e456429c1876c885fd1
Signed-off-by: Craig Stout <ed45f6f71b92aa13e468e9a189ebf82a3270af6a@ti.com>

omapzoom/platform-external-bltsville,omapzoom/platform-external-bltsville,omapzoom/platform-external-bltsville,omapzoom/platform-external-bltsville