drm/amdgpu: add VM eviction lock v3

This allows to invalidate VM entries without taking the reservation lock.

v3: use -EBUSY

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