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/board/freescale/m5373evb/nand.c b/board/freescale/m5373evb/nand.c
index 4c30d51..fdf3e0a 100644
--- a/board/freescale/m5373evb/nand.c
+++ b/board/freescale/m5373evb/nand.c
@@ -15,6 +15,7 @@
 #if defined(CONFIG_CMD_NAND)
 #include <nand.h>
 #include <linux/mtd/mtd.h>
+#include <linux/mtd/rawnand.h>
 
 #define SET_CLE		0x10
 #define SET_ALE		0x08