netxen: revert jumbo ringsize

Reducing jumbo ring size below 1024 reduces throughput for old
firmwares (3.4.216 and older) running on older (NX2031) chip,
so restore it back to 1024.

This was reduced in commit 32ec8033
("netxen: reduce memory footprint").

Raising jumbo ring size from 512 to 1024, adds ~4MB per port, but
there's still big saving because of original patch (~20MB per port).

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>