ext2: Correct maximum ext2 filesystem block size

Ext2 has traditionally supported filesystem block sizes upto page size
or upto 65536. Macro EXT2_MAX_BLOCK_SIZE is set to 4096, however that is
never used in ext2 so practically we always allowed whatever
sb_set_blocksize() accepted. Fix value of EXT2_MAX_BLOCK_SIZE because it
will be used in the next patch.
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/ext2.h

@@ -178,7 +178,7 @@ static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
  * Macro-instructions used to manage several block sizes
  */
 #define EXT2_MIN_BLOCK_SIZE		1024
-#define	EXT2_MAX_BLOCK_SIZE		4096
+#define	EXT2_MAX_BLOCK_SIZE		65536
 #define EXT2_MIN_BLOCK_LOG_SIZE		  10
 #define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)
 #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))