drm/amdgpu: fix contiguous handling for IB parsing v2

Otherwise we won't get correct access to the IB.

v2: keep setting AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS to avoid problems in
    the VRAM backend.

Signed-off-by: Christian König <christian.koenig@amd.com>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3501


Fixes: e362b7c8 ("drm/amdgpu: Modify the contiguous flags behaviour")
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Tested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>