e1000: Discard packets that are too long if !SBP and !LPE

The e1000_receive function for the e1000 needs to discard packets longer than
1522 bytes if the SBP and LPE flags are disabled. The linux driver assumes
this behavior and allocates memory based on this assumption.

Signed-off-by: Michael Contreras <michael@inetric.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
(cherry picked from commit b0d9ffcd)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>