bugfix: NanoBeam M5 XW hardware definition.

Adjust power levels to reflect what is in the board.info

This was likely a typo when I put the device in the first time.

In addition adjust naming to match Ubiquiti device rename.

{{{
board.sysid=0xe4e5
board.cpurevision=0x00001122
board.name=PowerBeam M5
board.shortname=P5B
board.subtype=400
board.netmodes=7
board.hwaddr=0418D65EEB39
board.reboot=40
board.upgrade=150
board.phycount=1
board.phy.1.maxmtu=2024
board.phy.2.maxmtu=2024
radio.1.name=
radio.1.shortname=
radio.1.bus=ahb
radio.1.subsystemid=0xe4e5
radio.1.subvendorid=0x0777
radio.1.txpower.max=26
radio.1.txpower.offset=4
radio.1.antennas=2
radio.1.def_antenna=1
radio.1.antenna.1.id=1
radio.1.antenna.1.name=400
radio.1.antenna.1.gain=25
radio.1.antenna.2.id=2
radio.1.antenna.2.name=Feed only
radio.1.antenna.2.gain=3
}}}

ref AREDN->ticket:185

Change-Id: I71d2a944b6abb9e30862d7ada7f46b80df2c731c

files/www/cgi-bin/perlfunc.pm

@@ -1295,11 +1295,11 @@ sub hardware_info
             'rfband'          => '2400',
          },
         '0xe4e5' => {
-            'name'            => 'NanoBeam M5 International',
-            'comment'         => 'NanoBeam M5 International XW series unsuported at this time',
+            'name'            => 'PowerBeam M5 400',
+            'comment'         => 'NanoBeam/PowerBeam M5 400',
             'supported'       => '-1',
             'maxpower'        => '22',
-            'pwroffset'       => '1',
+            'pwroffset'       => '4',
             'usechains'       => 1,
             'rfband'          => '5500',
          },