drm/amdgpu: Don't pin VRAM without DMABUF_MOVE_NOTIFY

Pinning of VRAM is for peer devices that don't support dynamic attachment
and move notifiers. But it requires that all such peer devices are able to
access VRAM via PCIe P2P. Any device without P2P access requires migration
to GTT, which fails if the memory is already pinned for another peer
device.

Sharing between GPUs should not require pinning in VRAM. However, if
DMABUF_MOVE_NOTIFY is disabled in the kernel build, even DMABufs shared
between GPUs must be pinned, which can lead to failures and functional
regressions on systems where some peer GPUs are not P2P accessible.

Disable VRAM pinning if move notifiers are disabled in the kernel build
to fix regressions when sharing BOs between GPUs.

Signed-off-by: Felix Kuehling <felix.kuehling@amd.com>
Tested-by: Hao (Claire) Zhou <hao.zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 05185812)