This patch adds yellow_carp_reg_base_init function to init the register
base for yellow carp.

v2: squash in updates (Alex)
Signed-off-by: NAaron Liu <aaron.liu@amd.com>
Reviewed-by: NHuang Rui <ray.huang@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>