NBIO handles misc bus io functions on the chip.  This
helper lib has the apppropriate functions for NBIO 7.0.
Signed-off-by: NChunming Zhou <David1.Zhou@amd.com>
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>