ARM: i.MX27 clk: dts: Use clock defines in DTS files

Use clock definitions in i.MX27 DTS files.
Additional changes included in this patch (imx27.dtsi):
- Fix IPG clock for UART6.
- Use EMI_AHB_GATE clock for WEIM.
- Added GPIO_IPG_GATE clock for GPIO nodes. Currently this clock is
  not used by the driver, but it can be added in the future.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>

arch/arm/boot/dts/imx27-pdk.dts

@@ -28,7 +28,7 @@
 		usbphy0: usbphy@0 {
 			compatible = "usb-nop-xceiv";
 			reg = <0>;
-			clocks = <&clks 0>;
+			clocks = <&clks IMX27_CLK_DUMMY>;
 			clock-names = "main_clk";
 		};
 	};

arch/arm/boot/dts/imx27-phytec-phycore-rdk.dts

@@ -61,7 +61,7 @@
 			compatible = "usb-nop-xceiv";
 			reg = <2>;
 			vcc-supply = <&reg_5v0>;
-			clocks = <&clks 0>;
+			clocks = <&clks IMX27_CLK_DUMMY>;
 			clock-names = "main_clk";
 		};
 	};

arch/arm/boot/dts/imx27-phytec-phycore-som.dtsi

@@ -51,7 +51,7 @@
 			compatible = "usb-nop-xceiv";
 			reg = <0>;
 			vcc-supply = <&sw3_reg>;
-			clocks = <&clks 0>;
+			clocks = <&clks IMX27_CLK_DUMMY>;
 			clock-names = "main_clk";
 		};
 	};