ext4: enable punch hole for bigalloc

After applied this commit (d23142c6), ext4 has supported punch hole for
a file system with bigalloc feature.  But we forgot to enable it.  This
commit fixes it.

Cc: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: NZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/inode.c

@@ -3501,11 +3501,6 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
 	if (!S_ISREG(inode->i_mode))
 		return -EOPNOTSUPP;
 
-	if (EXT4_SB(sb)->s_cluster_ratio > 1) {
-		/* TODO: Add support for bigalloc file systems */
-		return -EOPNOTSUPP;
-	}
-
 	trace_ext4_punch_hole(inode, offset, length);
 
 	/*