arm/arm64: configs: Remove the MFD_ prefix for MFD_CROS_EC_I2C/SPI symbols.

The cros-ec I2C and SPI transport drivers have been moved from MFD
subsystem to platform/chrome, at the same time, the config symbol has
been renamed and lost the MFD_ prefix, so update all configs to the new
config symbol name.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Benson Leung <bleung@chromium.org>