[MTD] [NOR] cfi_cmdset_0020.c: make a function static

This patch makes the needlessly global cfi_staa_erase_varsize() static.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/chips/cfi_cmdset_0020.c

@@ -893,7 +893,8 @@ retry:
 	return ret;
 }
 
-int cfi_staa_erase_varsize(struct mtd_info *mtd, struct erase_info *instr)
+static int cfi_staa_erase_varsize(struct mtd_info *mtd,
+				  struct erase_info *instr)
 {	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long adr, len;