e1000e: cleanup e1000_sw_lcd_config_ich8lan()

Do not acquire and release the PHY unnecessarily for parts that return
from this workaround without actually accessing the PHY registers.

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