staging: r8188eu: move out assignment in if condition

Should not use assignment in if condition.
Signed-off-by: Marcelo Aloisio da Silva <marcelo.as@aol.com>
Link: https://lore.kernel.org/r/20220218040140.GA22796@snoopySigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_cmd.c

@@ -1318,7 +1318,8 @@ static void c2h_wk_callback(struct work_struct *work)
 	evtpriv->c2h_wk_alive = true;
 
 	while (!rtw_cbuf_empty(evtpriv->c2h_queue)) {
-		if ((c2h_evt = (struct c2h_evt_hdr *)rtw_cbuf_pop(evtpriv->c2h_queue)) != NULL) {
+		c2h_evt = (struct c2h_evt_hdr *)rtw_cbuf_pop(evtpriv->c2h_queue);
+		if (c2h_evt) {
 			/* This C2H event is read, clear it */
 			rtw_write8(adapter, REG_C2HEVT_CLEAR, C2H_EVT_HOST_CLOSE);
 		} else {