anv: fix descriptor pool leak in VMA object

Quoting the spec :

   "When a pool is destroyed, all descriptor sets allocated from the
    pool are implicitly freed and become invalid. Descriptor sets
    allocated from a given pool do not need to be freed before
    destroying that descriptor pool."

This implies we might leak nodes allocated in the vma object.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 0a6d2593b8b63d ("anv: Allocate descriptor buffers from the BO cache")
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7796>
(cherry picked from commit 5d55ca9c300a6e240cf9216bba203321b7b44c90)
Change-Id: I231c0efffdc7337bcedd71c3aab0e3c658d91371
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/mesa/+/516360
Reviewed-by: John Rosasco <rosasco@google.com>
1 file changed