sata_inic162x: update intro comment, up the version and drop EXPERIMENTAL

sata_inic162x is now ready for production use.  Bump the version,
explain what's working and what's not and drop EXPERIMENTAL.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>