Hi,

This patch implements the set_ringparam(), one of the ethtool 
operations, which allows changing tx/rx ring sizes via ethtool.

Changelog:
- Changed memery allocation of tx/rx ring from static to dynamic
- Implemented set_ringparam()
- Tested on i386 and ppc64

Signed-off-by: Hubert WS Lin <wslin@tw.ibm.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>