Fix a read mbuf-after-free error in the iwi driver that was provoked by the trash allocator being used on mbufs.
Fix a read mbuf-after-free error in the iwi driver that was provoked by
the trash allocator being used on mbufs.

Reviewed by:	damien
Approved by:	re (scottl)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase