e1000e: cleanup: rename e1000e_id_led_init() and call as function pointer

Rename e1000e_id_led_init() to e1000e_id_led_init_generic() to signify the
function is used for more than one MAC-family type.  For the ich8lan MAC
family, some MACs use the generic function and others use the function
e1000_id_led_init_pchlan().  In all cases where e1000e_id_led_init() was
called directly, change to call the function pointer to be consistent with
the driver design.

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