staging: rtl8723au: Remove redundant casting in usb_ops_linux.c

Casting value returned by k[cmz]alloc is useless.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723au/hal/usb_ops_linux.c

@@ -382,8 +382,7 @@ static void usb_read_interrupt_complete(struct urb *purb)
 				struct evt_work *c2w;
 				int res;
 
-				c2w = (struct evt_work *)
-					kmalloc(sizeof(struct evt_work),
+				c2w = kmalloc(sizeof(struct evt_work),
 						GFP_ATOMIC);
 
 				if (!c2w) {