nand.h: Cleanup linux/mtd/rawnand.h usage

We only include <linux/mtd/rawnand.h> in <nand.h> for the forward
declaration of struct nand_chip, so do that directly.  Then, include
<linux/mtd/rawnand.h> where required directly.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/mtd/nand/raw/mxs_nand_spl.c b/drivers/mtd/nand/raw/mxs_nand_spl.c
index d16224a..6b70d68 100644
--- a/drivers/mtd/nand/raw/mxs_nand_spl.c
+++ b/drivers/mtd/nand/raw/mxs_nand_spl.c
@@ -13,6 +13,7 @@
 #include <linux/bitops.h>
 #include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/mtd/rawnand.h>
 
 static struct mtd_info *mtd;
 static struct nand_chip nand_chip;