RFE: add virtio-ccw support to zdev

[cohuck]

Currently, zdev does not support virtio-ccw devices, which makes the output of lszdev in a KVM guest kinda ugly. Example from one of my guests:

[root@localhost ~]# lscss                                  
Device   Subchan.  DevType CU Type Use  PIM PAM POM  CHPIDs           
----------------------------------------------------------------------
0.0.0000 0.0.0000  0000/00 3832/01 yes  80  80  ff   00000000 00000000
0.0.0001 0.0.0001  0000/00 3832/02 yes  80  80  ff   00000000 00000000
0.0.0002 0.0.0002  0000/00 3832/10 yes  80  80  ff   00000000 00000000
0.0.0003 0.0.0003  0000/00 3832/12 yes  80  80  ff   00000000 00000000
0.0.0004 0.0.0004  0000/00 3832/12 yes  80  80  ff   00000000 00000000
0.0.0005 0.0.0005  0000/00 3832/03 yes  80  80  ff   00000000 00000000
0.0.000a 0.0.0006  0000/00 3270/00      80  80  ff   01000000 00000000
0.0.1234 0.0.0007  3390/0e 3990/e9      f0  f0  ff   1a2a3a0a 00000000
[root@localhost ~]# lszdev                                 
TYPE         ID        ON   PERS  NAMES
dasd-eckd    0.0.1234  no   no    
generic-ccw  0.0.0000  yes  no    
generic-ccw  0.0.0001  yes  no    
generic-ccw  0.0.0002  yes  no    
generic-ccw  0.0.0003  yes  no    
generic-ccw  0.0.0004  yes  no    
generic-ccw  0.0.0005  yes  no    
generic-ccw  0.0.000a  no   no    

[Note that 3270 gets mapped to generic-ccw as well.]
While we don't have any special attributes for virtio-ccw devices, it still would be nice to add support

• for matching the devices to virtio-net, virtio-blk, etc.
• for adding related info to NAMES (e.g. vda for virtio-blk, eth0 for virtio-net)
  I think things like --by-path etc. could be quite useful.

Not terribly important; please consider this an "I'm feeling bored" type of enhancement :)

[hoeppnerj]

@oberpar can you have a look into it?

[borntraeger]

@mihajlov FYA.