e1000e: cleanup: rename e1000e_setup_link() and call as function pointer

Rename e1000e_setup_link() to e1000e_setup_link_generic() to signify the
function is used for more than one MAC-family type.  The 82571-family has
a custom setup_link function which also calls the generic function.  The
ich8lan-family has a custom function which should just be called via the
function pointer.  The 80003es2lan-family just uses the generic function.

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>