mtd, ubi, ubifs: resync with Linux-3.14

resync ubi subsystem with linux:

commit 455c6fdbd219161bd09b1165f11699d6d73de11c
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Mar 30 20:40:15 2014 -0700

    Linux 3.14

A nice side effect of this, is we introduce UBI Fastmap support
to U-Boot.

Signed-off-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Tom Rini <trini@ti.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Sergey Lapin <slapin@ossfans.org>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Joerg Krause <jkrause@posteo.de>
diff --git a/drivers/mtd/nand/ndfc.c b/drivers/mtd/nand/ndfc.c
index 5510b13..2659595 100644
--- a/drivers/mtd/nand/ndfc.c
+++ b/drivers/mtd/nand/ndfc.c
@@ -118,6 +118,7 @@
 		out_be32((u32 *)(base + NDFC_DATA), *p++);
 }
 
+#if defined(CONFIG_MTD_NAND_VERIFY_WRITE)
 static int ndfc_verify_buf(struct mtd_info *mtdinfo, const uint8_t *buf, int len)
 {
 	struct nand_chip *this = mtdinfo->priv;
@@ -130,6 +131,7 @@
 
 	return 0;
 }
+#endif
 
 /*
  * Read a byte from the NDFC.
@@ -205,7 +207,9 @@
 #endif
 
 	nand->write_buf  = ndfc_write_buf;
+#if defined(CONFIG_MTD_NAND_VERIFY_WRITE)
 	nand->verify_buf = ndfc_verify_buf;
+#endif
 	nand->read_byte = ndfc_read_byte;
 
 	chip++;