OMAP: DSS2: OMAPFB: Check fb2display() return value

Make sure NULL return value of fb2display() is not referenced. Found by
Coverity.
Signed-off-by: Jani Nikula <ext-jani.1.nikula@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>

drivers/video/omap2/omapfb/omapfb-ioctl.c

@@ -858,7 +858,7 @@ int omapfb_ioctl(struct fb_info *fbi, unsigned int cmd, unsigned long arg)
 			break;
 		}
 
-		if (!display->driver->enable_te) {
+		if (!display || !display->driver->enable_te) {
 			r = -ENODEV;
 			break;
 		}

drivers/video/omap2/omapfb/omapfb-main.c

@@ -1271,6 +1271,9 @@ static int omapfb_blank(int blank, struct fb_info *fbi)
 	int do_update = 0;
 	int r = 0;
 
+	if (!display)
+		return -EINVAL;
+
 	omapfb_lock(fbdev);
 
 	switch (blank) {