e1000e: ESB2 config after link up

On ESB2, the MAC-to-PHY (Kumeran) interface must be configured after link
is up before any traffic is sent; a new PHY operations function pointer is
provided for this.  To facilitate read/write of the Kumeran registers
without blocking PHY register writes, the driver/firmware synchronization
method which previously used a hardware semaphore for both PHY and Kumeran
register accesses is now split.  New Kumeran register read/write functions
utilize this new synchronization method.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>