arm64: dts: imx8mq-reform2: add uSDHC2 CD pinctrl

The SD card slot on the Reform 2 uses the card detect pad routed to
the uSDHC2 module as intended. This is currently working as it is the
default mux setting for this pad, but better be explicit and add it
to the pinctrl node.
Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-mnt-reform2.dts

@@ -202,6 +202,7 @@ MX8MQ_IOMUXC_UART2_TXD_UART2_DCE_TX		0x45
 
 	pinctrl_usdhc2: usdhc2grp {
 		fsl,pins = <
+			MX8MQ_IOMUXC_SD2_CD_B_USDHC2_CD_B		0x0
 			MX8MQ_IOMUXC_SD2_CLK_USDHC2_CLK			0x83
 			MX8MQ_IOMUXC_SD2_CMD_USDHC2_CMD			0xc3
 			MX8MQ_IOMUXC_SD2_DATA0_USDHC2_DATA0		0xc3