[PATCH] S2io: MSI/MSI-X support (runtime configurable)

This patch adds support for MSI/MSI-X feature to the driver.  It is
a runtime parameter(for now, loadable parameter).  Default is INTA.

Patch has been tested on IA64 platform with Xframe II adapter,
both of which support MSI-X feature.  An improvement of about 7%
in throughput(both Tx and Rx) was observed and a reduction by 7%
in CPU utilization during Tx test.

Signed-off-by: Ravinandan Arakali <ravinandan.arakali@neterion.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>