events: allow callbacks per CQ, QP, or SRQ

events: allow callbacks per CQ, QP, or SRQ

The underlying hardware drivers both support setting callbacks on a per
widget (CQ, QP, or SRQ) basis, but the verbs interface only allows one
global event handler and one completion handler for the HCA.  Modify the
verbs interface to allow setting events callbacks directly on the HCA
objects.  This allows the HCA to support multiple consumers of its
interface, and users can optimize their event handling based on the call.
For example, the HCA drivers can invoke callbacks directly to the ULPs
without the calls first being filtered by IBAL.  This will improve
completion event reporting.

To minimize changes to the existing stack, the current event handler is
used for all events, regardless of type.  Optimizations are left for a
separate patch.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
git-svn-id: svn://openib.tc.cornell.edu/gen1/trunk@1435 ad392aa1-c5ef-ae45-8dd8-e69d62a5ef86