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/tegra_nand.c b/drivers/mtd/nand/raw/tegra_nand.c
index 6310253..8e70c8e 100644
--- a/drivers/mtd/nand/raw/tegra_nand.c
+++ b/drivers/mtd/nand/raw/tegra_nand.c
@@ -19,6 +19,7 @@
 #include <linux/bug.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
+#include <linux/mtd/rawnand.h>
 #include <asm/gpio.h>
 #include <fdtdec.h>
 #include <bouncebuf.h>