bnx2x: Correct logic for pvid configuration.

Commit 05cc5a39

 ("bnx2x: add vlan filtering offload") has introduced
an incorrect logic for checking whether pvid should be configured for
a vf, causing the hypervisor driver to send unneeded ramrods for all of
the vfs each time a pvid has changed.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>