Use gfx ras common initialization interface to
initialize gfx ras block.

V2:
  Update function call due to amdgpu_gfx_ras_sw_init
interface changes.
Signed-off-by: YiPeng Chai <YiPeng.Chai@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>