drm/omap: remove warn from debugfs

Patch dfe96ddcfa22b44100814b9435770f6ff1309d37 (omapdrm: simplify locking in
the fb debugfs file) removed taking locks when using omapdrm's debugfs
to dump fb objects.

However, in omap_gem_describe we give a WARN is the lock has not been
taken, so that WARN is now seen every time omapdrm debugfs is used.

So, presuming the removal of locks is ok, we can also remove the WARN.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

diff --cc drivers/gpu/drm/omapdrm/omap_gem.c
Simple merge