mfd: Fix wl1273 warning

Remove the unused variable "u16 val" of wl1273-core.c.

Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wl1273-core.c

@@ -153,7 +153,6 @@ out:
  */
 static int wl1273_fm_set_volume(struct wl1273_core *core, unsigned int volume)
 {
-	u16 val;
 	int r;
 
 	if (volume > WL1273_MAX_VOLUME)