boards: arc: hsdk: Fix building of LED build_all test

tests/drivers/build_all/led/drivers.led.build fails to build
since the GPIO driver for the cypress,cy8c95xx-gpio is not
enabled.  This is because the I2C bus is not enabled.  Add
enabling the I2C bus if GPIO is enabled to address the issue.

Signed-off-by: Kumar Gala <galak@kernel.org>