camcontrol: No need to set CAM_ARG_[PG]LIST in defects

We can or in the the list_format bits directly if we or in the
list_format when we look it up the first time. Free up CAM_ARG_[PG]LIST
from the CAM_ARG_xxx enum.

Sponsored by: Netflix
Reviewed by: mav (I made his suggested change)
Differential Revision: https://reviews.freebsd.org/D40523