cpu/x86/mp_init: Print amount of time it takes in bsp_do_flight_plan

Since the timeout in bsp_do_flight_plan is bumped up to 1 second, this
change adds a print to indicate the amount of time it takes for all the
APs to check-in.

TEST=Verified on Nami that it prints:
"bsp_do_flight_plan done after 395 msecs."

Change-Id: I4c8380e94305ed58453ed18b341b3b923949d7a8
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/25044
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/cpu/x86/mp_init.c b/src/cpu/x86/mp_init.c
index 23aea14..409caa5 100644
--- a/src/cpu/x86/mp_init.c
+++ b/src/cpu/x86/mp_init.c
@@ -547,6 +547,9 @@
 	const int timeout_us = 1000000;
 	const int step_us = 100;
 	int num_aps = mp_params->num_cpus - 1;
+	struct stopwatch sw;
+
+	stopwatch_init(&sw);
 
 	for (i = 0; i < mp_params->num_records; i++) {
 		struct mp_flight_record *rec = &mp_params->flight_plan[i];
@@ -566,6 +569,9 @@
 
 		release_barrier(&rec->barrier);
 	}
+
+	printk(BIOS_INFO, "%s done after %ld msecs.\n", __func__,
+	       stopwatch_duration_msecs(&sw));
 	return ret;
 }