drm/amdgpu: remove nonsense in_interrupt() checks

might_sleep() is supposed to raise if warning if called in interrupt or
atomic context.

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