drm/amdgpu: Fix two reset triggered in a row

Some times a hang GPU causes multiple reset sources to schedule resets.
The second source will be able to trigger an unnecessary reset if they
schedule after we call amdgpu_device_stop_pending_resets.

Move amdgpu_device_stop_pending_resets to after the reset is done. Since
at this point the GPU is supposedly in a good state, any reset scheduled
after this point would be a legitimate reset.

Remove unnecessary and incorrect checks for amdgpu_in_reset that was
kinda serving this purpose.

Signed-off-by: Yunxiang Li <Yunxiang.Li@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>