Staging: sxg: Make SXG driver use MSI-X interrupts if possible

Make Sahara SXG driver use MSI-X interrupts instead of line based interrupts
if possible. In case of problems in getting MSI-X vectors or MSI-X not being
supported, driver will fall back to use previous line based interrupts.

Signed-off-by: LinSysSoft Sahara Team <saharaproj@linsyssoft.com>
Signed-off-by: Mithlesh Thukral <mithlesh@linsyssoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>