arm64: dts: imx8mn-beacon: Fix SPI CS pinmux

The final production baseboard had a different chip select than
earlier prototype boards.  When the newer board was released,
the SPI stopped working because the wrong pin was used in the device
tree and conflicted with the UART RTS. Fix the pinmux for
production boards.

Fixes: 36ca3c8 ("arm64: dts: imx: Add Beacon i.MX8M Nano development kit")
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: aford173

arch/arm64/boot/dts/freescale/imx8mn-beacon-baseboard.dtsi

@@ -81,7 +81,7 @@
 &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 {
@@ -202,7 +202,7 @@
 			MX8MN_IOMUXC_ECSPI2_SCLK_ECSPI2_SCLK		0x82
 			MX8MN_IOMUXC_ECSPI2_MOSI_ECSPI2_MOSI		0x82
 			MX8MN_IOMUXC_ECSPI2_MISO_ECSPI2_MISO		0x82
-			MX8MN_IOMUXC_ECSPI1_SS0_GPIO5_IO9		0x41
+			MX8MN_IOMUXC_ECSPI2_SS0_GPIO5_IO13		0x41
 		>;
 	};