umass: should the device specific information be moved from C code to the text file?

[Yuri]

Currently all devices supported by umass driver are listed in
* sys/dev/usb/usbdevs
  - which has vendor table (vendor-id/name)
  - and product table (ref-to-vendor-id/product-id/name)
and
* sys/dev/usb/umass.c
  - which has some per-device flags.

The problem with this way is that some people might want to disable 
umass for particular devices.
For example some people prefer to use gphoto2 with usb-cameras and 
gphoto2 needs the device to be ugen.

I suggest device specific information should be moved from 
sys/dev/usb/usbdevs and sys/dev/usb/umass.c
to some text file (ex. /etc/umass-devices) which would be read by umass 
driver when it's loaded.

This way users will be able to easily remove/add entries without the 
need to recompile the module.

Yuri