anv: Fix vm bind of imported buffers

anv: Fix vm bind of imported buffers

Imported buffers may be created in a device with different
memory alignment and this can cause vm bind to fail because bo
size can be smaller than the calculated vm bind range using the
importer device memory alignment.

So here adding actual_size to anv_bo, this will be set with the actual
size of the bo allocated by kmd for bos allocate in the current device.
For other bo the lseek or the Vulkan API size will be used.

Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22219>