ARM: mxs: get reset address from device tree

Instead of using static address definition, get reset address from
device tree with mapping, so that core_initcall mxs_arch_reset_init()
can be killed.

The "rtc" clock code in mxs_arch_reset_init() seems to be zombie, since
there is no clk lookup defined in clock driver at all.  Remove it
together.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx28.dtsi

@@ -756,7 +756,7 @@
 			ranges;
 
 			clks: clkctrl@80040000 {
-				compatible = "fsl,imx28-clkctrl";
+				compatible = "fsl,imx28-clkctrl", "fsl,clkctrl";
 				reg = <0x80040000 0x2000>;
 				#clock-cells = <1>;
 			};