ARM: dts: imx28: rename mmc2_sck_cfg

This patch renames mmc2_sck_cfg in order to prepare for an alternative
muxing setup.
Signed-off-by: Michael Heimpold <michael.heimpold@i2se.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx28-m28cu3.dts

@@ -57,7 +57,7 @@ ssp2: ssp@80014000 {
 				pinctrl-names = "default";
 				pinctrl-0 = <&mmc2_4bit_pins_a
 					     &mmc2_cd_cfg
-					     &mmc2_sck_cfg>;
+					     &mmc2_sck_cfg_a>;
 				bus-width = <4>;
 				vmmc-supply = <&reg_vddio_sd1>;
 				status = "okay";

arch/arm/boot/dts/imx28.dtsi

@@ -613,7 +613,8 @@ MX28_PAD_AUART1_RX__SSP2_CARD_DETECT
 					fsl,pull-up = <MXS_PULL_DISABLE>;
 				};
 
-				mmc2_sck_cfg: mmc2-sck-cfg {
+				mmc2_sck_cfg_a: mmc2-sck-cfg@0 {
+					reg = <0>;
 					fsl,pinmux-ids = <
 						MX28_PAD_SSP0_DATA7__SSP2_SCK
 					>;