f2fs: remove redundant check from f2fs_setflags_common()

Now that f2fs_ioc_setflags() and f2fs_ioc_fssetxattr() call the VFS
helper functions which check for permission to change the immutable and
append-only flags, it's no longer needed to do this check in
f2fs_setflags_common() too.  So remove it.

This is based on a patch from Darrick Wong, but reworked to apply after
commit 36098557 ("f2fs: separate f2fs i_flags from fs_flags and ext4
i_flags").

Originally-from: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -1653,19 +1653,12 @@ static int f2fs_file_flush(struct file *file, fl_owner_t id)
 static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
 {
 	struct f2fs_inode_info *fi = F2FS_I(inode);
-	u32 oldflags;
 
 	/* Is it quota file? Do not allow user to mess with it */
 	if (IS_NOQUOTA(inode))
 		return -EPERM;
 
-	oldflags = fi->i_flags;
-
-	if ((iflags ^ oldflags) & (F2FS_APPEND_FL | F2FS_IMMUTABLE_FL))
-		if (!capable(CAP_LINUX_IMMUTABLE))
-			return -EPERM;
-
-	fi->i_flags = iflags | (oldflags & ~mask);
+	fi->i_flags = iflags | (fi->i_flags & ~mask);
 
 	if (fi->i_flags & F2FS_PROJINHERIT_FL)
 		set_inode_flag(inode, FI_PROJ_INHERIT);