pinctrl: mediatek: mt7988: remove _base from reg-names

The reg-names in mt7988.dtsi have no _base suffix. Remove the suffix
will also make it match upstream linux format.

Fixes: 8c2cb748ef5 (pinctrl: mediatek: mt7988: rename reg-names to upstream linux format)
diff --git a/drivers/pinctrl/mediatek/pinctrl-mt7988.c b/drivers/pinctrl/mediatek/pinctrl-mt7988.c
index 1f384e8..639e241 100644
--- a/drivers/pinctrl/mediatek/pinctrl-mt7988.c
+++ b/drivers/pinctrl/mediatek/pinctrl-mt7988.c
@@ -1233,8 +1233,7 @@
 };
 
 static const char *const mt7988_pinctrl_register_base_names[] = {
-	"gpio_base", "iocfg_tr_base", "iocfg_br_base", "iocfg_rb_base",
-	"iocfg_lb_base", "iocfg_tl_base",
+	"gpio", "iocfg_tr", "iocfg_br", "iocfg_rb", "iocfg_lb", "iocfg_tl",
 };
 
 static const struct mtk_pinctrl_soc mt7988_data = {