md: fix integer as NULL pointer warnings in md.c

drivers/md/md.c:734:16: warning: Using plain integer as NULL pointer
drivers/md/md.c:1115:16: warning: Using plain integer as NULL pointer

Add some braces to match the else-block as well.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/md/md.c

@@ -731,9 +731,9 @@ static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version
 	else
 		rdev->desc_nr = sb->this_disk.number;
 
-	if (refdev == 0)
+	if (!refdev) {
 		ret = 1;
-	else {
+	} else {
 		__u64 ev1, ev2;
 		mdp_super_t *refsb = (mdp_super_t*)page_address(refdev->sb_page);
 		if (!uuid_equal(refsb, sb)) {
@@ -1116,9 +1116,9 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
 	else
 		rdev->desc_nr = le32_to_cpu(sb->dev_number);
 
-	if (refdev == 0)
+	if (!refdev) {
 		ret = 1;
-	else {
+	} else {
 		__u64 ev1, ev2;
 		struct mdp_superblock_1 *refsb = 
 			(struct mdp_superblock_1*)page_address(refdev->sb_page);