drivers: gpio: Convert drivers to new DT device macros

Convert gpio drivers to use new DT variants of the DEVICE APIs.
    DEVICE_AND_API_INIT -> DEVICE_DT_DEFINE
    DEVICE_GET -> DEVICE_DT_GET
    DEVICE_DECLARE -> DEVICE_DT_INST_DECLARE

etc..

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>