cq: allow polling with an array of wc's

cq: allow polling with an array of wc's

Allow polling for a list of work completions using an array of
completion structures, rather than a linked list.  This avoids needing
to walk the list to link the structures together before calling poll,
which is a fast path operation.

A new completion structure is added that provides the qp_context
associated with a completion.  This avoids changes to the existing
ULPs, while taking advantage of the underlying UVP capabilities.
Providing the qp_context is useful when dealing with SRQ.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
git-svn-id: svn://openib.tc.cornell.edu/gen1@1437 ad392aa1-c5ef-ae45-8dd8-e69d62a5ef86