v2:
   1. drop the special handling for the hw IP
      suggested by hawking and Christian.
   2. refine the variable name suggested by Flora.

This funciton as the entry of gfx off feature.
we arbitrat gfx off feature enable/disable in this
function.
Reviewed-by: NHawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: NRex Zhu <Rex.Zhu@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>