mtd: mtdswap: fix possible null dereference

This patch fixes the possible null dereference of the variable "oinfo"
Thanks to Coverity for spotting this.

Signed-off-by: Maxin B. John <john.maxin@nokia.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/mtdswap.c

@@ -1450,7 +1450,13 @@ static void mtdswap_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 	}
 
 	oinfo = mtd->ecclayout;
-	if (!mtd->oobsize || !oinfo || oinfo->oobavail < MTDSWAP_OOBSIZE) {
+	if (!oinfo) {
+		printk(KERN_ERR "%s: mtd%d does not have OOB\n",
+			MTDSWAP_PREFIX, mtd->index);
+		return;
+	}
+
+	if (!mtd->oobsize || oinfo->oobavail < MTDSWAP_OOBSIZE) {
 		printk(KERN_ERR "%s: Not enough free bytes in OOB, "
 			"%d available, %zu needed.\n",
 			MTDSWAP_PREFIX, oinfo->oobavail, MTDSWAP_OOBSIZE);