mtd: Stop updating erase_info->state and calling mtd_erase_callback()

MTD users are no longer checking erase_info->state to determine if the
erase operation failed or succeeded. Moreover, mtd_erase_callback() is
now a NOP.

We can safely get rid of all mtd_erase_callback() calls and all
erase_info->state assignments. While at it, get rid of the
erase_info->state field, all MTD_ERASE_XXX definitions and the
mtd_erase_callback() function.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Bert Kenward <bkenward@solarflare.com>
---
Changes in v2:
- Address a few coding style issues (reported by Miquel)
- Remove comments that are no longer valid (reported by Miquel)

include/linux/mtd/mtd.h

@@ -30,12 +30,6 @@
 
 #include <asm/div64.h>
 
-#define MTD_ERASE_PENDING	0x01
-#define MTD_ERASING		0x02
-#define MTD_ERASE_SUSPEND	0x04
-#define MTD_ERASE_DONE		0x08
-#define MTD_ERASE_FAILED	0x10
-
 #define MTD_FAIL_ADDR_UNKNOWN -1LL
 
 struct mtd_info;
@@ -49,7 +43,6 @@ struct erase_info {
 	uint64_t addr;
 	uint64_t len;
 	uint64_t fail_addr;
-	u_char state;
 };
 
 struct mtd_erase_region_info {
@@ -589,8 +582,6 @@ extern void register_mtd_user (struct mtd_notifier *new);
 extern int unregister_mtd_user (struct mtd_notifier *old);
 void *mtd_kmalloc_up_to(const struct mtd_info *mtd, size_t *size);
 
-void mtd_erase_callback(struct erase_info *instr);
-
 static inline int mtd_is_bitflip(int err) {
 	return err == -EUCLEAN;
 }