Fix for commit 3f9cb1c14dc368f41447db5f78d6248c4f100ad4

Here's a patch to fix the issue introduced by me, as Reimar Döffinger pointed out,

Reimar Döffinger wrote:
> On Thu, Aug 13, 2009 at 03:01:20PM +0300, Naphtali Sprei wrote:
>> Bug fix for segfault when run as i82551 HW:
>> Use Extended TBD only when HW supports it (i82558 and up).
>>
>> Added assertions to guard from such buffer overflow
>> Introduce the MAX_TCB_BYTE_COUNT macro
>> Allocate buf big enough as HW needs (MAX_ETH_FRAME_SIZE -> MAX_TCB_BYTE_COUNT)
>>
>>
>> I don't feel 100% OK with the "s->device >= i82558B" condition
>> since it relies on the numeric (hex) value of those defines, which currently
>> is correct, but changes (which I don't forsee now) might break it.
>
> It seems this was applied. Unfortunately this breaks things on FreeBSD.
> There seem to be multiple issues.
> First, the intel document says the 82551, 82550, 82559 models are all
> supersets of the 82558. Or in other words: they all support this
> feature.
> Only the 82557 does not.
> But then even for that the FreeBSD driver will fail.
> The reason for that is this line:
>     eeprom_contents[0xa] = 0x4000;
> the value here must be 0x01000 for all 82557 models it seems.

 Correct the logic of determining devices that supports
 extended TxCB: only the 82557 do not support it.

Signed-off-by: Naphtali Sprei <nsprei@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
