mtd: map: Don't use "proxy" headers

Update header inclusions to follow IWYU (Include What You Use)
principle.

Note that kernel.h is discouraged to be included as it's written
at the top of that file.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

include/linux/mtd/map.h

@@ -8,15 +8,15 @@
 #ifndef __LINUX_MTD_MAP_H__
 #define __LINUX_MTD_MAP_H__
 
-#include <linux/types.h>
-#include <linux/list.h>
-#include <linux/string.h>
 #include <linux/bug.h>
-#include <linux/kernel.h>
 #include <linux/io.h>
-
+#include <linux/ioport.h>
+#include <linux/string.h>
+#include <linux/types.h>
 #include <linux/unaligned.h>
-#include <asm/barrier.h>
+
+struct device_node;
+struct module;
 
 #ifdef CONFIG_MTD_MAP_BANK_WIDTH_1
 #define map_bankwidth(map) 1
@@ -188,6 +188,7 @@ typedef union {
    of living.
 */
 
+struct mtd_chip_driver;
 struct map_info {
 	const char *name;
 	unsigned long size;