sf: fix erase debug output

We want to show the length, so multiplying by sector size makes no sense.
This is a hold over from the erase code before the big refactor.

Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

drivers/mtd/spi/spi_flash.c

@@ -233,8 +233,7 @@ int spi_flash_cmd_erase(struct spi_flash *flash, u8 erase_cmd,
 			goto out;
 	}
 
-	debug("SF: Successfully erased %zu bytes @ %#x\n",
-	      len * erase_size, start);
+	debug("SF: Successfully erased %zu bytes @ %#x\n", len, start);
 
  out:
 	spi_release_bus(flash->spi);