linux-wandboard

isci: enable interrupts during controller start, and flush discovery

Polling the event queue during scan is an unneeded holdover from the
original driver.

Signed-off-by: Edmund Nadolski <edmund.nadolski@intel.com>
[djbw: ensure we flush all port events and domain discovery]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>