qla3xxx: device doesnt do hardware checksumming.

Reading the code for ql_hw_csum_setup(), it is obvious that
this driver is broken for IPV6. The driver sets the NETIF_F_HW_SUM
flag, but the code for checksum setup only deals with IPV4.

Compile tested only, no hardware available.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>