mrp: debug updates

This commit updates debug output (no functional changes)
- adds mrpd_log_printf() which timestamps all output messages
- fixes debug strings in mrp_state_string()
- adds logging of timer start/stop operations
- renames MRP event debug strings to match those spec'd in 802.1Q
- update debug output update for client SND and RECV messages
mrpd: add timer running flags
mrpd: add timer running debug output
mrpd: call lvatimer stop on MRP_EVENT_LVATIMER
mrpd: don't (re)start jointimer if it is already running.
mrpd: MSVC version, add mrpd_log_printf() implementation.
mrpd: MSVC version, correct mrp_schedule_tx_event() implementation.
mrpd: debug updates
mrpd: support ARM build