ARM: mediatek: Add earlyprintk support for mt6589

Enable low-level debug for Mediatek mt6589 SoC on UART0.
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/Kconfig.debug

@@ -842,6 +842,14 @@ choice
 		  Say Y here if you want kernel low-level debugging support
 		  on Ux500 based platforms.
 
+	config DEBUG_MT6589_UART0
+		bool "Mediatek mt6589 UART0"
+		depends on ARCH_MEDIATEK
+		select DEBUG_UART_8250
+		help
+		  Say Y here if you want kernel low-level debugging support
+		  for Mediatek mt6589 based platforms on UART0.
+
 	config DEBUG_VEXPRESS_UART0_DETECT
 		bool "Autodetect UART0 on Versatile Express Cortex-A core tiles"
 		depends on ARCH_VEXPRESS && CPU_CP15_MMU
@@ -1083,6 +1091,7 @@ config DEBUG_UART_PHYS
 	default 0x10126000 if DEBUG_RK3X_UART1
 	default 0x101f1000 if ARCH_VERSATILE
 	default 0x101fb000 if DEBUG_NOMADIK_UART
+	default 0x11006000 if DEBUG_MT6589_UART0
 	default 0x16000000 if ARCH_INTEGRATOR
 	default 0x18000300 if DEBUG_BCM_5301X
 	default 0x1c090000 if DEBUG_VEXPRESS_UART0_RS1
@@ -1146,6 +1155,7 @@ config DEBUG_UART_VIRT
 	default 0xf01fb000 if DEBUG_NOMADIK_UART
 	default 0xf0201000 if DEBUG_BCM2835
 	default 0xf1000300 if DEBUG_BCM_5301X
+	default 0xf1006000 if DEBUG_MT6589_UART0
 	default 0xf11f1000 if ARCH_VERSATILE
 	default 0xf1600000 if ARCH_INTEGRATOR
 	default 0xf1c28000 if DEBUG_SUNXI_UART0