ARM: imx_v6_v7_defconfig: Disable CONFIG_IMX_IPUV3_CORE

For now we'll use our internal IPUv3 common driver, so this patch
disables CONFIG_IMX_IPUV3_CORE from upstream kernel.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
[Leonard: Remove unrelated changes]
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>