ARM: mxs: add initial device tree support for imx28-evk board

This patch includes basic dt support which can boot via nfs rootfs.

Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Marek Vasut <marex@denx.de>

drivers/clk/mxs/clk-imx28.c

@@ -142,6 +142,7 @@ static struct clk_lookup hbus_lookups[] __initdata = {
 
 static struct clk_lookup xbus_lookups[] __initdata = {
 	{ .dev_id = "duart", .con_id = "apb_pclk"},
+	{ .dev_id = "80074000.serial", .con_id = "apb_pclk"},
 	{ .dev_id = "mxs-dma-apbx", },
 	{ .dev_id = "80024000.dma-apbx", },
 };