boards: xtensa: intel_s1000_crb: enable gpio0

gpio0 is used by the tlv320dac310x reset-gpios, however, it was not
enabled. In general, UART and GPIO are enabled by default as they fall
into the category of minimal peripherals. An alternative solution would
be to add an overlay to the sample.

The intel_s1000_crb board sample was actually broken, however, it got
unnoticed because it uses device_get_binding(), meaning the error would
show up at runtime.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>