soc: mediatek: pwrap: add missing check on rstc

The variable rstc is set only when the SoC PWRAP have the
PWRAP_CAP_RESET capability. Check whether rstc is set before
using it to avoid errors.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/mediatek/mtk-pmic-wrap.c

@@ -1478,7 +1478,8 @@ static int pwrap_init(struct pmic_wrapper *wrp)
 {
 	int ret;
 
-	reset_control_reset(wrp->rstc);
+	if (wrp->rstc)
+		reset_control_reset(wrp->rstc);
 	if (wrp->rstc_bridge)
 		reset_control_reset(wrp->rstc_bridge);