staging: wilc1000: change handle_set_operation_mode's return type to void

When handle_set_operation_mode is called in hostIFthread that is a
kernel thread, it is not checked return type of this function. This
patch changes return type to void and removes braces if statement due to
have a single statement.
Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/host_interface.c

@@ -328,7 +328,7 @@ static void handle_set_wfi_drv_handler(struct wilc_vif *vif,
 		netdev_err(vif->ndev, "Failed to set driver handler\n");
 }
 
-static s32 handle_set_operation_mode(struct wilc_vif *vif,
+static void handle_set_operation_mode(struct wilc_vif *vif,
 				      struct op_mode *hif_op_mode)
 {
 	s32 result = 0;
@@ -345,12 +345,8 @@ static s32 handle_set_operation_mode(struct wilc_vif *vif,
 	if ((hif_op_mode->mode) == IDLE_MODE)
 		complete(&hif_driver_comp);
 
-	if (result) {
+	if (result)
 		netdev_err(vif->ndev, "Failed to set driver handler\n");
-		return -EINVAL;
-	}
-
-	return result;
 }
 
 static s32 handle_set_ip_address(struct wilc_vif *vif, u8 *ip_addr, u8 idx)