dm init: fix const confusion for dm_allowed_targets array

A non const pointer to const cannot be marked initconst.
Mark the array actually const.

Fixes: 6bbc923d dm: add support to directly boot to a mapped device
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-init.c

@@ -36,7 +36,7 @@ struct dm_device {
 	struct list_head list;
 };
 
-const char *dm_allowed_targets[] __initconst = {
+const char * const dm_allowed_targets[] __initconst = {
 	"crypt",
 	"delay",
 	"linear",