arm64: dts: imx8mm-beacon: Fix ecspi2 pinmux

Early hardware did not support hardware handshaking on the UART, but
final production hardware did.  When the hardware was updated the chip
select was changed to facilitate hardware handshaking on UART3.  Fix the
ecspi2 pin mux to eliminate a pin conflict with UART3 and allow the
EEPROM to operate again.

Fixes: 4ce01ce3 ("arm64: dts: imx8mm-beacon: Enable RTS-CTS on UART3")
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm-beacon-baseboard.dtsi

@@ -120,7 +120,7 @@ &csi {
 &ecspi2 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_espi2>;
-	cs-gpios = <&gpio5 9 GPIO_ACTIVE_LOW>;
+	cs-gpios = <&gpio5 13 GPIO_ACTIVE_LOW>;
 	status = "okay";
 
 	eeprom@0 {
@@ -316,7 +316,7 @@ pinctrl_espi2: espi2grp {
 			MX8MM_IOMUXC_ECSPI2_SCLK_ECSPI2_SCLK		0x82
 			MX8MM_IOMUXC_ECSPI2_MOSI_ECSPI2_MOSI		0x82
 			MX8MM_IOMUXC_ECSPI2_MISO_ECSPI2_MISO		0x82
-			MX8MM_IOMUXC_ECSPI1_SS0_GPIO5_IO9		0x41
+			MX8MM_IOMUXC_ECSPI2_SS0_GPIO5_IO13              0x41
 		>;
 	};