ARM: dts: imx6sll-evk: avoid underscores in node name

usdhc1 and usdhc3 node name contain underscores, so replace the
'_' by '-'.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sll-evk.dts

@@ -463,7 +463,7 @@ MX6SLL_PAD_SD1_DATA3__SD1_DATA3	0x17059
 		>;
 	};
 
-	pinctrl_usdhc1_100mhz: usdhc1grp_100mhz {
+	pinctrl_usdhc1_100mhz: usdhc1grp-100mhz {
 		fsl,pins = <
 			MX6SLL_PAD_SD1_CMD__SD1_CMD	0x170b9
 			MX6SLL_PAD_SD1_CLK__SD1_CLK	0x130b9
@@ -474,7 +474,7 @@ MX6SLL_PAD_SD1_DATA3__SD1_DATA3	0x170b9
 		>;
 	};
 
-	pinctrl_usdhc1_200mhz: usdhc1grp_200mhz {
+	pinctrl_usdhc1_200mhz: usdhc1grp-200mhz {
 		fsl,pins = <
 			MX6SLL_PAD_SD1_CMD__SD1_CMD	0x170f9
 			MX6SLL_PAD_SD1_CLK__SD1_CLK	0x130f9
@@ -551,7 +551,7 @@ MX6SLL_PAD_REF_CLK_32K__GPIO3_IO22	0x17059
 		>;
 	};
 
-	pinctrl_usdhc3_100mhz: usdhc3grp_100mhz {
+	pinctrl_usdhc3_100mhz: usdhc3grp-100mhz {
 		fsl,pins = <
 			MX6SLL_PAD_SD3_CMD__SD3_CMD		0x170a1
 			MX6SLL_PAD_SD3_CLK__SD3_CLK		0x130a1
@@ -563,7 +563,7 @@ MX6SLL_PAD_REF_CLK_32K__GPIO3_IO22	0x17059
 		>;
 	};
 
-	pinctrl_usdhc3_200mhz: usdhc3grp_200mhz {
+	pinctrl_usdhc3_200mhz: usdhc3grp-200mhz {
 		fsl,pins = <
 			MX6SLL_PAD_SD3_CMD__SD3_CMD		0x170e9
 			MX6SLL_PAD_SD3_CLK__SD3_CLK		0x130f9