ARM64: copy CONFIG_CMDLINE_EXTEND from ARM

Copy the config choice for CONFIG_CMDLINE_EXTEND from
arch/arm/Kconfig, including CONFIG_CMDLINE_FROM_BOOTLOADER
as the default.  These will be used by drivers/of/fdt.c.

Change-Id: I8416038498ddf8fc1e99ab06109825eb1492aa7f
Signed-off-by: Colin Cross <ccross@android.com>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 524abc4..01be844 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -943,6 +943,23 @@
 	  entering them here. As a minimum, you should specify the the
 	  root device (e.g. root=/dev/nfs).
 
+choice
+	prompt "Kernel command line type" if CMDLINE != ""
+	default CMDLINE_FROM_BOOTLOADER
+
+config CMDLINE_FROM_BOOTLOADER
+	bool "Use bootloader kernel arguments if available"
+	help
+	  Uses the command-line options passed by the boot loader. If
+	  the boot loader doesn't provide any, the default kernel command
+	  string provided in CMDLINE will be used.
+
+config CMDLINE_EXTEND
+	bool "Extend bootloader kernel arguments"
+	help
+	  The command-line arguments provided by the boot loader will be
+	  appended to the default kernel command string.
+
 config CMDLINE_FORCE
 	bool "Always use the default kernel command string"
 	help
@@ -950,6 +967,7 @@
 	  loader passes other arguments to the kernel.
 	  This is useful if you cannot or don't want to change the
 	  command-line options your boot loader passes to the kernel.
+endchoice
 
 config EFI_STUB
 	bool