e1000e: implement ethtool set_phys_id

Based on a patch from Stephen Hemminger <shemminger@vyatta.com>.

The new ethtool set_phys_id takes over controlling the LED for
identifying boards.  This fixes the lockout during that period.
For this device lots of extra infrastructure can also be removed by
using set_phys_id.

v2: - return blink frequency for parts that do not support blink in h/w
    - add blink_led function pointers for devices that do support blink
      in h/w to cleanup the test for this functionality

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>