kernel: fix whiteout rename on ubifs (FS#579)

This was apparently caused by some linux upstream merge damage

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/generic/patches-4.9/031-ubifs-fix-RENAME_WHITEOUT-support.patch

@@ -0,0 +1,25 @@
+From: Felix Fietkau <nbd@nbd.name>
+Date: Mon, 6 Mar 2017 09:48:52 +0100
+Subject: [PATCH] ubifs: fix RENAME_WHITEOUT support
+
+Remove faulty leftover check in do_rename(), apparently introduced in a
+merge that combined whiteout support changes with commit f03b8ad8d386
+("fs: support RENAME_NOREPLACE for local filesystems")
+
+Fixes: 9e0a1fff8db5 ("ubifs: Implement RENAME_WHITEOUT")
+Cc: stable@vger.kernel.org
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+---
+
+--- a/fs/ubifs/dir.c
++++ b/fs/ubifs/dir.c
+@@ -1088,9 +1088,6 @@ static int do_rename(struct inode *old_d
+ 	struct timespec time;
+ 	unsigned int uninitialized_var(saved_nlink);
+ 
+-	if (flags & ~RENAME_NOREPLACE)
+-		return -EINVAL;
+-
+ 	/*
+ 	 * Budget request settings: deletion direntry, new direntry, removing
+ 	 * the old inode, and changing old and new parent directory inodes.