[magma] Switch to magma_buffer_export

Change-Id: I025983d5b4311260fc9015679e57fc2d892bad58
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/github.com/intel/media-driver/+/807855
Reviewed-by: John Bauman <jbauman@google.com>
1 file changed