sys: Remove $FreeBSD$: one-line .c comment pattern

Remove /^/[*/]\s*\$FreeBSD\$.*\n/

urtw: switch to ieee80211_add_channel_list_2ghz().

- Use device's channel list instead of default one (from
ieee80211_init_channels()).
- Add ic_getradiocaps() method.

Fix undefined behavior: (1 << 31) is not defined as 1 is an int and this
shifts into the sign bit. Instead use (1U << 31) which gets the
expected result.

This fix is not ideal as it assumes a 32 bit int, but does fix the issue
for most cases.

A similar change was made in OpenBSD.

Discussed with: -arch, rdivacky
Reviewed by: cperciva

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

MFC r197761,r198194,r198862

updates device entries supported with the product name not magic numbers
and sorts entries. WUSB54GCV2 is added.

overhauls urtw(4) for supporting RTL8187B devices properly that there
was major changes to initialize RF chipset and set H/W registers and
removed a lot of magic numbers on code.

overhauls urtw(4) for supporting RTL8187B devices properly that there
was major changes to initialize RF chipset and set H/W registers and
removed a lot of magic numbers on code. Details are as follows:

- uses the endpoint 0x89 to get TX status information which used to
get TX complete or retry numbers or get a beacon interrupt. It's
only valuable for RTL8187B.
- removes urtw_write[8|16|32]_i functions that it's useless now.
- uses ic->ic_updateslot to set SLOT, SIFS, DIES, EIFS, CW_VAL
registers that doesn't set these whenever the channel is changed.
- code for initializing RF chipset for RTL8187B changed a lot that
there was many problems on TX transfers so it doesn't work properly
even if just for a ping/pong. Now it becomes more stable than
before that TX throughputs using netperf(1) were about 15 ~ 17Mbps/s
though sometimes it encounters packet losses.
- removes a lot of magic numbers that in the previous all of
representing RX and TX descriptors were consisted of magic numbers
and structures. It'd be more readable rather than before.
- calculates TX duration more accurately for urtw(4) devices.
- style(9)

ports urtw(4) for USB2. Additionally it supports a 8187B chipset weakly
that it needs more stabilization.