Improve Brocade FabricOS device information and sensor detection

I wrote a patch to improve Brocade Fibre Channel switch device information display and sensor discovery.

Device information now displays Brocade part number for FabricOS device, unfortunately device model (like Silkworm 5000 etc) is not available through SNMP so part number must do. In addition device serial number is detected correctly now.

Device discovery detects now temperature and fan speed sensors, however power supply present flag (0 or 1) is mistakenly interpreted as fan speed but that should be trivial to fix, I think.