tests: Verify SBS Gauge driver on qemu_cortex_a9

The SBS Gauge driver is tested on a nucleo_f070rb board. This is an ARM
board so we should also verify on some Qemu emulated ARM platform.

Enable SBS Gauge driver test on an ARM platform, arbitrarily chosen as
qemu_cortex_a9.

TEST=twister -T tests/drivers/sensor/sbs_gauge

Signed-off-by: Aaron Massey <aaronmassey@google.com>