em28xx debug module parameters

Hi Mauro,

is there a chance that we can clean up the em28xx debug module parameter mess ?
There are currently 8 (!) of them.
Do we have to maintain them all forever as "stable userspace interface" ?

For example:
- "reg_debug" is actually used for usb control message debugging
- "core_debug" is abused for usb isoc debugging and not used for anything else
- there is a module parameter "isoc_debug", too, but it is used by em28xx-v4l only
...

Regards,
Frank