ipg: fix an unsigned widening cast of '~' truncation issue

The bug here is this code from ipg_nic_hard_start_xmit():

	txfd->tfc &= cpu_to_le64(~IPG_TFC_TFDDONE);

IPG_TFC_TFDDONE is 0x0000000080000000 so it's an unsigned int.  The
negated value is 0x7fffffff but 0xffffffff7fffffff was intended.

The other values in this file don't need to be changed but I did it for
consistency.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>