dm vdo indexer: prevent unterminated string warning

Fix array initialization that triggers a warning:

error: initializer-string for array of ‘unsigned char’ is too long
 [-Werror=unterminated-string-initialization]

Signed-off-by: Chung Chung <cchung@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

Author: C2Redhat

drivers/md/dm-vdo/indexer/index-layout.c

@@ -54,7 +54,6 @@
  * Each save also has a unique nonce.
  */
 
-#define MAGIC_SIZE 32
 #define NONCE_INFO_SIZE 32
 #define MAX_SAVES 2
 
@@ -98,9 +97,11 @@ enum region_type {
 #define SUPER_VERSION_CURRENT 3
 #define SUPER_VERSION_MAXIMUM 7
 
-static const u8 LAYOUT_MAGIC[MAGIC_SIZE] = "*ALBIREO*SINGLE*FILE*LAYOUT*001*";
+static const u8 LAYOUT_MAGIC[] = "*ALBIREO*SINGLE*FILE*LAYOUT*001*";
 static const u64 REGION_MAGIC = 0x416c6252676e3031; /* 'AlbRgn01' */
 
+#define MAGIC_SIZE (sizeof(LAYOUT_MAGIC) - 1)
+
 struct region_header {
 	u64 magic;
 	u64 region_blocks;