Restore original, 2018 mtrace_event(atomic) spin lock logic

Fixes bad commit b284ac32b5 ("debugability: Macro Metaprogramming
Refactor") that accidentally swapped mtrace_event() and
mtrace_event_atomic()

Before that accidental inversion, _trace_event_mboxN() functions invoked
spin_lock_irq() whereas _trace_even_mbox_atomicN() did NOT take
locks. That was consistent with the non-mbox, DMA variants of these
functions. As explained in the message of commit 3dca7b7778 ("trace:
dma: Add atomic and nowait DMA tracing support."), functions with the
`_atomic()` suffix,, are meant to be used in atomic contexts where the
lock is _already_ taken.

Searching for spin_lock_irq() in the code after the bad commit shows
that the logic was inverted for the _mbox variants: the lock became used
for the _atomic() variants.

The reasons why I can't reproduce any actual issue are likely the same
reasons why this inversion was never noticed:

- no multicore
- very little use of trace_.*_atomic variants
- spin_lock_irq() is re-entrant?

I merely noticed the inconsistency with DMA tracing while trying to
solve unrelated issues in the same places.

The non-mbox, DMA variants were not affected by the bad commit because
for DMA the lock was and is managed in a different file: dma-trace.c.

Searching "spin_lock_irq" in later commit b12a6626c5 ("trace:
Remove metaprogramming from trace implementation") shows that it
preserved this inversion across this second refactor; it left the bug
untouched.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

src/trace/trace.c

@@ -250,11 +250,11 @@ static void vatrace_log(bool send_atomic, uint32_t log_entry, const struct tr_ct
 #if CONFIG_TRACEM
 	/* send event by mail box too. */
 	if (send_atomic) {
+		mtrace_event((const char *)data, MESSAGE_SIZE(arg_count));
+	} else {
 		spin_lock_irq(&trace->lock, flags);
 		mtrace_event((const char *)data, MESSAGE_SIZE(arg_count));
 		spin_unlock_irq(&trace->lock, flags);
-	} else {
-		mtrace_event((const char *)data, MESSAGE_SIZE(arg_count));
 	}
 #else
 	/* send event by mail box if level is LOG_LEVEL_CRITICAL. */