drm/amdgpu: coding style of amdgpu_vm_is_gpu_reset

The name is a bit confusing and the extra "? true : false" is superflous.

Additional to that remove setting the reset counter directly after checking it.

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