ibacm: Introduce loopback resolution 'protocol'

ibacm: Introduce loopback resolution 'protocol'

OFED 1.5.2 introduced a kernel patch that disables looping
back multicast messages to the sending QP.  This capability
was enabled by default.  The current ACM address resolution
protocol depends on this feature of multicast.  To handle
the case where multicast loopback has been disabled, add an
option to ACM to resolve loopback addresses using local data
only.  This option is enabled by default.

When loopback resolution is set to 'local', ACM will automatically
insert a loopback destination into each endpoint.  Requests
to resolve a loopback address will find this destination
and use it to respond to client requests.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>