arm64: zynqmp: Add SD1 level shifter mode to alternative selection

Extend Kconfig to cover SD1 level shifter mode.

Reported-by: Jason Wu <jason.hy.wu@gmail.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/cpu/armv8/zynqmp/Kconfig b/arch/arm/cpu/armv8/zynqmp/Kconfig
index fb1247c..3f922b4 100644
--- a/arch/arm/cpu/armv8/zynqmp/Kconfig
+++ b/arch/arm/cpu/armv8/zynqmp/Kconfig
@@ -102,6 +102,7 @@
 	default 0x7 if USB_MODE
 	default 0xa if SW_USBHOST_MODE
 	default 0xb if SW_SATA_MODE
+	default 0xe if SD1_LSHFT_MODE
 
 choice
 	prompt "Boot mode"
@@ -138,6 +139,9 @@
 config SW_SATA_MODE
 	bool "SW SATA_MODE"
 
+config SD1_LSHFT_MODE
+	bool "SD1_LSHFT_MODE"
+
 endchoice
 
 endif