dm writecache: fix the maximum number of arguments

Advance the maximum number of arguments to 16.
This fixes issue where certain operations, combined with table
configured args, exceed 10 arguments.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 48debafe4f2f ("dm: add writecache target")
Cc: stable@vger.kernel.org # v4.18+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 1ea923a..7d277de 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -2041,7 +2041,7 @@ static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	struct wc_memory_superblock s;
 
 	static struct dm_arg _args[] = {
-		{0, 10, "Invalid number of feature args"},
+		{0, 16, "Invalid number of feature args"},
 	};
 
 	as.argc = argc;