ocfs2: use s_maxbytes directly in ocfs2_change_file_space()

There's no need to recalculate things via ocfs2_max_file_offset() as we've
already done that to fill s_maxbytes, so use that instead. We can also
un-export ocfs2_max_file_offset() then.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 992eb56..7e508e2 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1533,7 +1533,7 @@
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	struct buffer_head *di_bh = NULL;
 	handle_t *handle;
-	unsigned long long max_off = ocfs2_max_file_offset(inode->i_sb->s_blocksize_bits);
+	unsigned long long max_off = inode->i_sb->s_maxbytes;
 
 	if (ocfs2_is_hard_readonly(osb) || ocfs2_is_soft_readonly(osb))
 		return -EROFS;