* Unconditionally turn on SIOCGI2C probing for all interfaces
    on "ifconfig -v". I've seen no measurable timing difference
    for doing additional SIOCGI2C call for system with 4k vlans.
* Determine appropriate handler (SFP/QSFP) by reading identification
    byte (which is the same for both SFF-8472 and SFF-8436) instead
   of checking driver name.

MFC with:	r270064
Sponsored by:	Yandex LLC