[PATCH] e1000: Added disable packet split capability

Adds the ability to disability packet split at compile time and use the legacy receive path on PCI express hardware.  Made this a CONFIG option and modified the Kconfig, to reflect the new option.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>