timekeeping: Prints the amounts of time spent during suspend

In addition to keeping a histogram of suspend times, also
print out the time spent in suspend to dmesg.

This helps to keep track of suspend time while debugging using
kernel logs.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: NRuchi Kandoi <kandoiruchi@google.com>
[jstultz: Tweaked commit message]
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

kernel/time/timekeeping_debug.c

@@ -75,5 +75,7 @@ void tk_debug_account_sleep_time(struct timespec64 *t)
 	int bin = min(fls(t->tv_sec), NUM_BINS-1);
 
 	sleep_time_bin[bin]++;
+	pr_info("Suspended for %lld.%03lu seconds\n", (s64)t->tv_sec,
+			t->tv_nsec / NSEC_PER_MSEC);
 }