ixgbe: fdb: only allow NUD_PERM fdb entries

There was a bitwise operation error in the fdb_add block
that was only allowing FDB types that were not permanent.

This was the opposite of the intent because the hardware
never ages out address these are the _only_ type of addrs
that should be allowed.

This was missed because until recently iproute2 did not
set any bit for this by default. And our test code to
manage FDB entries on embedded devices similarly did not
set these bits.

I am going to chalk this up as a bug and fix it now.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>