ARM i.MX27: Add devicetree support

This patch adds basic devicetree support for i.MX27 based SoCs.
Only the bindings for which drivers exist are added here:

- UART
- fec
- CSPI
- I2C
- watchdog
- gpio

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 4defb97b..85433b9 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -376,6 +376,14 @@
 	  Include support for IMX27 IPCAM platform. This includes specific
 	  configurations for the board and its peripherals.
 
+config MACH_IMX27_DT
+	bool "Support i.MX27 platforms from device tree"
+	select SOC_IMX27
+	select USE_OF
+	help
+	  Include support for Freescale i.MX27 based platforms
+	  using the device tree for discovery
+
 endif
 
 if ARCH_IMX_V6_V7