This adds soc21 common ip block support

Changed from v1:
Switch WREG32/RREG32_PCIE to use indirect reg access
helper for sco15 and onwards
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Stanley.Yang <Stanley.Yang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>