Split iscsi ctl frontend off of ctl(4) as ctl_iscsi(4)
The goal of this work is to remove the (now) explicit dependency for ctl(4)
on iscsi(4), so end-users without iscsi(4) support in the kernel can use
ctl(4) for its other functions.
This allows those without iscsi(4) support built into the kernel (like
my employer) to use ctl(4) as a test mechanism (which was doable around the
10.0-RELEASE period, but broken between 10.0-RELEASE and 11.0-RELEASE).
This also unbreaks the ctl(4) device in GENERIC as iscsi(4) support isn't
built into that kernel as part of that config.
Add a manpage for the new ctl(4) frontend device, ctl_iscsi(4).
MFC after: 2 weeks
Relnotes: yes
Sponsored by: Dell EMC Isilon