If we pass down 64k - L2 hdr size + 1 to 64K L3+ data adding an ether header will make the data go over the 64k limits announced to busdma as maxsize and the transaction will fail.
If we pass down 64k - L2 hdr size + 1 to 64K L3+ data adding an ether
header will make the data go over the 64k limits announced to busdma as
maxsize and the transaction will fail.

With TSO this can result in a TCP regression due to the lost packet.

According to the data sheets ixgbe(4) 82598 and 82599 can handle up to
256k so increase the maximum.

Reported by:	Jon Kåre Hellan, UNINETT (jon.kare.hellan uninett.no)
Tested by:	Jon Kåre Hellan, UNINETT (jon.kare.hellan uninett.no)
MFC after:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase