arm64: defconfig: Enable ptn5150 extcon driver

Enable the extcon driver for NXP PTN5150A chips (CC logic for USB Type-C
applications) present on some of i.MX8 evaluation boards (e.g. Variscite
Symphony board).

Link: https://lore.kernel.org/r/20200817065654.4419-2-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Olof Johansson <olof@lixom.net>