arm64: defconfig: Enable GPIO_SYSCON

roc-rk3328-cc board has vcc_sdio regulator controlled by a special
output only gpio pin. This special pin can now be reference as
<&grf_gpio 0> via gpio-syscon driver, as mentioned in below commit.

commit <99165b93

> ("arm64: dts: rockchip: add sdmmc UHS support for
roc-rk3328-cc")

So, enable bydefault on the defconfig.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Link: https://lore.kernel.org/r/20230719102427.3617577-1-jagan@amarulasolutions.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>