imx8mm-venice-gw700x: prepare to synchronise device trees with linux

As a preparatory step remove the pinctrl_pmic reference which does not
exist in the Linux upistream device tree.

This avoids the following error once synchronised:

+Error: arch/arm/dts/imx8mm-venice-gw700x-u-boot.dtsi:26.1-14 Label or
 path pinctrl_pmic not found

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
diff --git a/arch/arm/dts/imx8mm-venice-gw700x-u-boot.dtsi b/arch/arm/dts/imx8mm-venice-gw700x-u-boot.dtsi
index c15e623..e877580 100644
--- a/arch/arm/dts/imx8mm-venice-gw700x-u-boot.dtsi
+++ b/arch/arm/dts/imx8mm-venice-gw700x-u-boot.dtsi
@@ -22,7 +22,3 @@
 &{/soc@0/bus@30800000/i2c@30a20000/pmic@69/regulators} {
 	u-boot,dm-spl;
 };
-
-&pinctrl_pmic {
-	u-boot,dm-spl;
-};