drm/amdgpu:don't invoke srio-gpu-reset in gpu-reset (v2)

because we don't want to do sriov-gpu-reset under certain
cases, so just split those two funtion and don't invoke
sr-iov one from bare-metal one.

V2:
remove debugfs_gpu_reset routine on SRIOV case.

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>