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>