arm64: dts: s32g: Disable usdhc write-protect

arm64: dts: s32g: Disable usdhc write-protect

NXP S32G2/S32G3 SoC based platforms do not
use a pin for SD-Card write protection used by
the uSDHC controller.

Hence, adding 'disable-wp' usdhc device-tree property in order to fix
observed warnings on SD boot as the following:
"host does not support reading read-only switch, assuming write-enable"

Signed-off-by: Ciprian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-by: Matthias Brugger <mbrugger@suse.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>