ARM: vf610: add UART choice for low-level debug

Add choice for low-level debug UART. Similar to i.MX6, there is a
numeric configuration, valid choices are 0 to 3.
Note that the kernel assumes that the boot loader initialized clock
properly.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index eab8ecb..00c6950 100644
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -942,6 +942,15 @@
 	  Choose UART port on which kernel low-level debug messages
 	  should be output.
 
+config DEBUG_VF_UART_PORT
+	int "Vybrid Debug UART Port Selection" if DEBUG_VF_UART
+	default 1
+	range 0 3
+	depends on SOC_VF610
+	help
+	  Choose UART port on which kernel low-level debug messages
+	  should be output.
+
 config DEBUG_TEGRA_UART
 	bool
 	depends on ARCH_TEGRA