qlcnic: reduce rx ring size

If eswitch is enabled, rcv ring size can be reduce, as
physical port is partition-ed.

Signed-off-by: Sony Chacko <sony.chacko@qlogic.com>
Signed-off-by: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>