sf: unify erase commands

Analysis of the flash drivers shows that they all use 0x20 if the erase
size is 4KiB, or 0xd8 if it's larger.  So with this info in hand, we can
unify all the erase functionality in one place.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/drivers/mtd/spi/macronix.c b/drivers/mtd/spi/macronix.c
index 894b1ca..5268c66 100644
--- a/drivers/mtd/spi/macronix.c
+++ b/drivers/mtd/spi/macronix.c
@@ -35,11 +35,6 @@
 
 #include "spi_flash_internal.h"
 
-/* MX25xx-specific commands */
-#define CMD_MX25XX_SE		0x20	/* Sector Erase */
-#define CMD_MX25XX_BE		0xD8	/* Block Erase */
-#define CMD_MX25XX_CE		0xc7	/* Chip Erase */
-
 struct macronix_spi_flash_params {
 	u16 idcode;
 	u16 nr_blocks;
@@ -123,11 +118,6 @@
 	return ret;
 }
 
-static int macronix_erase(struct spi_flash *flash, u32 offset, size_t len)
-{
-	return spi_flash_cmd_erase(flash, CMD_MX25XX_BE, offset, len);
-}
-
 struct spi_flash *spi_flash_probe_macronix(struct spi_slave *spi, u8 *idcode)
 {
 	const struct macronix_spi_flash_params *params;
@@ -156,7 +146,7 @@
 	flash->name = params->name;
 
 	flash->write = spi_flash_cmd_write_multi;
-	flash->erase = macronix_erase;
+	flash->erase = spi_flash_cmd_erase;
 	flash->read = spi_flash_cmd_read_fast;
 	flash->page_size = 256;
 	flash->sector_size = 256 * 16 * 16;