mpxyd,mcm: changes for backward compatibility with older v4 MIC clients

mpxyd,mcm: changes for backward compatibility with older v4 MIC clients

Allow mpxyd service to run with older MIC clients that support only proxy-out
and not proxy-in capabilities. Define minimal and compatible versions and
sync to MIC client during device open.

Create and use dat_mcm_msg_compat, dat_mix_mr_compat, and dat_mix_cm_compat
messages and operations with older v4 clients.

Move current MIX command version to v5.

Signed-off-by: Arlin Davis <arlin.r.davis@intel.com>