ARM: imx_v6_v7_defconfig: Remove CONFIG_SOC_LS1021A

imx_v6_v7_defconfig is not suitable for booting LS1021 as it needs
LPAE.

Remove this option.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NShawn Guo <shawnguo@kernel.org>

arch/arm/configs/imx_v6_v7_defconfig

@@ -42,7 +42,6 @@ CONFIG_SOC_IMX6SL=y
 CONFIG_SOC_IMX6SX=y
 CONFIG_SOC_IMX6UL=y
 CONFIG_SOC_IMX7D=y
-CONFIG_SOC_LS1021A=y
 CONFIG_SOC_VF610=y
 CONFIG_PCI=y
 CONFIG_PCI_IMX6=y