drivers: uart: Convert drivers to new DT device macros

Convert uart drivers from:

	DEVICE_AND_API_INIT -> DEVICE_DT_INST_DEFINE
	DEVICE_GET -> DEVICE_DT_INST_GET
	DEVICE_DECLARE -> DEVICE_DT_INST_DECLARE

etc..

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