mtd: rawnand: Keep all internal stuff private

A lot of things defined in rawnand.h should not be exposed to NAND
controller drivers and should only be shared by core files.

Create the drivers/mtd/nand/raw/internals.h header to store such
definitions, and move all private defs to this header.

Also remove EXPORT_SYMBOLS() on functions that are not supposed to be
exposed.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
diff --git a/drivers/mtd/nand/raw/nand_hynix.c b/drivers/mtd/nand/raw/nand_hynix.c
index 7eec0d9..ac1b5c1 100644
--- a/drivers/mtd/nand/raw/nand_hynix.c
+++ b/drivers/mtd/nand/raw/nand_hynix.c
@@ -15,10 +15,11 @@
  * GNU General Public License for more details.
  */
 
-#include <linux/mtd/rawnand.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
 
+#include "internals.h"
+
 #define NAND_HYNIX_CMD_SET_PARAMS	0x36
 #define NAND_HYNIX_CMD_APPLY_PARAMS	0x16