drm/omap: silence unititialized variable warning

Smatch complains that "area_free" could be used without being
initialized.  This code is several years old and premusably works fine
so this can't be a very serious bug.  But it's easy enough to silence
the warning.  If "area_free" is false at the end of the function then
we return -ENOMEM.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180418142937.GA13828@mwanda


Signed-off-by: Sean Paul <seanpaul@chromium.org>