qlcnic: Fix PVID configuration on eSwitch port.

Clear older PVID before adding a newer PVID to the eSwicth port

Signed-off-by: Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>
Signed-off-by: Shahed Shaikh <shahed.shaikh@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>