mtd: Add export.h for EXPORT_SYMBOL/THIS_MODULE where needed

These two common macros will be no longer present everywhere.
Call out the include needs of them explicitly where required.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/mtd/mtdsuper.c

@@ -14,6 +14,7 @@
 
 #include <linux/mtd/super.h>
 #include <linux/namei.h>
+#include <linux/export.h>
 #include <linux/ctype.h>
 #include <linux/slab.h>
 

drivers/mtd/nand/nand_bbt.c

@@ -67,6 +67,7 @@
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/vmalloc.h>
+#include <linux/export.h>
 
 static int check_pattern_no_oob(uint8_t *buf, struct nand_bbt_descr *td)
 {

drivers/mtd/onenand/onenand_bbt.c

@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/onenand.h>
+#include <linux/export.h>
 
 /**
  * check_short_pattern - [GENERIC] check if a pattern is in the buffer

drivers/mtd/ubi/vmt.c

@@ -26,6 +26,7 @@
 #include <linux/err.h>
 #include <linux/math64.h>
 #include <linux/slab.h>
+#include <linux/export.h>
 #include "ubi.h"
 
 #ifdef CONFIG_MTD_UBI_DEBUG