arm64: dts: imx8x-colibri-iris-v2: Fix pinctrl node names

arm64: dts: imx8x-colibri-iris-v2: Fix pinctrl node names

Per fsl,scu-pinctrl.yaml, the pinctrl node names should end with 'grp'.

Change them to fix the following schema warning:

imx8qxp-colibri-iris-v2.dtb: pinctrl: 'enable_3v3_vmmc', 'lcd-lvds' do not match any of the regexes: 'grp$', 'pinctrl-[0-9]+'
	from schema $id: http://devicetree.org/schemas/pinctrl/fsl,scu-pinctrl.yaml#

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>