ARM: multi_v7_defconfig: Enable i.MX6SLL SoC

Enable i.MX6SLL SoC which is already supported by mainline kernel.

Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/configs/multi_v7_defconfig

@@ -43,6 +43,7 @@ CONFIG_SOC_IMX51=y
 CONFIG_SOC_IMX53=y
 CONFIG_SOC_IMX6Q=y
 CONFIG_SOC_IMX6SL=y
+CONFIG_SOC_IMX6SLL=y
 CONFIG_SOC_IMX6SX=y
 CONFIG_SOC_IMX6UL=y
 CONFIG_SOC_LS1021A=y