e1000: FIX: firmware handover bits

Upon code inspection it was spotted that the firmware handover bit get/set
mismatched, which may have resulted in management issues on PCI-E
adapters. Setting them correctly may fix some management issues such
as arp routing etc.

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>