mtd: pfow: remove unused variable

Fixes warning:

In file included from drivers/mtd/lpddr/qinfo_probe.c:31:0:
include/linux/mtd/pfow.h: In function ‘send_pfow_command’:
include/linux/mtd/pfow.h:104:6: warning: variable ‘chipnum’ set but not used [-Wunused-but-set-variable]
  int chipnum;
      ^
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

include/linux/mtd/pfow.h

@@ -101,9 +101,6 @@ static inline void send_pfow_command(struct map_info *map,
 				unsigned long len, map_word *datum)
 {
 	int bits_per_chip = map_bankwidth(map) * 8;
-	int chipnum;
-	struct lpddr_private *lpddr = map->fldrv_priv;
-	chipnum = adr >> lpddr->chipshift;
 
 	map_write(map, CMD(cmd_code), map->pfow_base + PFOW_COMMAND_CODE);
 	map_write(map, CMD(adr & ((1<<bits_per_chip) - 1)),