Making IB a first class citizen.

[Alfred Perlstein]

Hello -net.

This email is about making Infiniband a first class citizen of the 
FreeBSD kernel.

Right now we have one #ifdef OFED in the src tree that makes compiling 
modules a real challenge:

In sys/net/if_llatbl.h the "struct llentry" size changes based on if 
OFED is compiled in or not, only by 16 bytes because Infiniband uses 
20bytes for MAC.  I am wondering if it would be OK to just unifdef this 
part to make inifiband a first class citizen of the kernel. Otherwise 
maybe we can reverse the ifdef so that it's WITHOUT_OFED and by default 
have it on.

I understand that we can not do this for FreeBSD 9.x due to breaking 
network ABI, however I think we still have time to do so in FreeBSD 10.x.

If there's no objection I'd like to push this change into head in the 
next day or two.  The only difference is +16 bytes to the "struct llentry".

Comments?