ARM: dts: imx6sx-sabreauto: drop board specific pinctrl container node

The board specific pinctrl function container node 'imx6x-sabreauto' is
not really necessary, since commit 5fcdf6a7 ("pinctrl: imx: Allow
parsing DT without function nodes").  Let's drop it to save one level of
indentation.
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sx-sabreauto.dts

@@ -66,7 +66,6 @@ &usdhc4 {
 };
 
 &iomuxc {
-	imx6x-sabreauto {
 	pinctrl_uart1: uart1grp {
 		fsl,pins = <
 			MX6SX_PAD_GPIO1_IO04__UART1_TX		0x1b0b1
@@ -139,5 +138,4 @@ pinctrl_vcc_sd3: vccsd3grp {
 			MX6SX_PAD_KEY_COL1__GPIO2_IO_11		0x17059
 		>;
 	};
-	};
 };