drm/omap: check return value from soc_device_match

drm/omap: check return value from soc_device_match

[ Upstream commit 4d6cb5e2fee52af17001e92950f0894304706ee4 ]

soc_device_match() can return NULL, so add a check and fail if
soc_device_match() fails.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180502091159.7071-2-tomi.valkeinen@ti.com
Reviewed-by: Benoit Parrot <bparrot@ti.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>