t530: Move to common gpio.h inrastructure

Change-Id: I5cf6dbab64f3eda02e6418be65f21e28ddf0d9ff
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7125
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>