IB/ipath: New sysfs entries to control 7220 features

IBA7220 includes many more configurable IB settings. Getting/setting
these is now grouped into a pair of chip specific functions accessed via
function pointers.  Provide sysfs access to these settings.

Signed-off-by: Michael Albaugh <michael.albaugh@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>