kernel: drop mtd_pad_erasesize() helper from 4.9 and 4.14

It has been last used in kernel 3.18 for uimage and squashfs splitters
embedded in the mtdpart.c.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

target/linux/generic/pending-4.9/404-mtd-add-more-helper-functions.patch

@@ -11,25 +11,7 @@ Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
 
 --- a/drivers/mtd/mtdpart.c
 +++ b/drivers/mtd/mtdpart.c
-@@ -763,6 +763,17 @@ run_parsers_by_type(struct mtd_part *sla
- 	return nr_parts;
- }
- 
-+static inline unsigned long
-+mtd_pad_erasesize(struct mtd_info *mtd, int offset, int len)
-+{
-+	unsigned long mask = mtd->erasesize - 1;
-+
-+	len += offset & mask;
-+	len = (len + mask) & ~mask;
-+	len -= offset & mask;
-+	return len;
-+}
-+
- #ifdef CONFIG_MTD_SPLIT_FIRMWARE_NAME
- #define SPLIT_FIRMWARE_NAME	CONFIG_MTD_SPLIT_FIRMWARE_NAME
- #else
-@@ -1225,6 +1236,24 @@ int mtd_is_partition(const struct mtd_in
+@@ -1225,6 +1225,24 @@ int mtd_is_partition(const struct mtd_in
  }
  EXPORT_SYMBOL_GPL(mtd_is_partition);