ARM: multi_v7_defconfig: Enable support for missing ChromeOS EC drivers

Enable the needed Kconfig options to have support for the ChromeOS EC
I2C transport, I2C tunnel and chardev user-space interface.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>