In the event that the ID command timed out, mps(4)/mpr(4) did not free the
command until it could be cancelled. However, it freed the associated
buffer (cm_data). Fix the lifetime issue by freeing the associated buffer
only after Abort Task or controller reset.
Reviewed by: scottl
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D18612