MFC r218056:

MFC r218056:

Fix bug in the netfront driver that caused excessive packet drops during
receive processing.

Remove unnecessary restrictions on the mbuf chain length built during an
LRO receive.  This restriction was copied from the Linux netfront driver
where the LRO implementation cannot handle more than 18 discontinuities.
The FreeBSD implementation has no such restriction.

Approved by:	gibbs (private e-mail)

git-svn-id: svn://svn.freebsd.org/base/stable/8@222867 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f