turnip/magma: buffer fixes

- free gem handle after we're done using the struct tu_bo
- free vmo mappings
- fix handle close on Fuchsia
- handle vk_alloc fail

Bug:475911788
Change-Id: Ideaad470d939b1f06cdb990eddfd3a70d3f85fd8
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/mesa/+/1466499
Commit-Queue: Craig Stout <cstout@google.com>
Reviewed-by: David Gilhooley <dgilhooley@google.com>
1 file changed