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

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>
[ This is a security vulnerability, CVE-2012-6075 / XSA-41. ]
(cherry picked from commit 4c2cae2a882db4d2a231b27b3b31a5bbec6dacbf)