fs/reiserfs/reiserfs.c: Fix compiler warning

Fix:
reiserfs.c: In function 'reiserfs_mount':
reiserfs.c:360:22: warning: dereferencing type-punned pointer
will break strict-aliasing rules [-Wstrict-aliasing]

Signed-off-by: Anatolij Gustschin <agust@denx.de>

fs/reiserfs/reiserfs.c

@@ -282,6 +282,7 @@ reiserfs_mount (unsigned part_length)
 {
   struct reiserfs_super_block super;
   int superblock = REISERFS_DISK_OFFSET_IN_BYTES >> SECTOR_BITS;
+  char *cache;
 
   if (part_length < superblock + (sizeof (super) >> SECTOR_BITS)
       || ! reiserfs_devread (superblock, 0, sizeof (struct reiserfs_super_block),
@@ -357,7 +358,8 @@ reiserfs_mount (unsigned part_length)
   if (! block_read (sb_root_block(&super), 0, INFO->blocksize, (char*) ROOT))
     return 0;
 
-  INFO->tree_depth = __le16_to_cpu(BLOCKHEAD (ROOT)->blk_level);
+  cache = ROOT;
+  INFO->tree_depth = __le16_to_cpu(BLOCKHEAD (cache)->blk_level);
 
 #ifdef REISERDEBUG
   printf ("root read_in: block=%d, depth=%d\n",