Revert "[PATCH] e1000: disable TSO on the 82544 with slab debugging"

This reverts commit 72f3ab74, which was
superceded by commit 683a2aa3


("e1000: Do not truncate TSO TCP header with 82544 workaround"), which
fixed the real problem.

Signed-off-by: Jeff Garzik <jeff@garzik.org>