timekeeping: export get_monotonic_coarse64 symbol

EXPORT_SYMBOL() get_monotonic_coarse64 for new IIO timestamping clock
selection usage. This provides user apps the ability to request a
particular IIO device to timestamp samples using a monotonic coarse clock
granularity.
Signed-off-by: NGregor Boirie <gregor.boirie@parrot.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

kernel/time/timekeeping.c

@@ -2186,6 +2186,7 @@ struct timespec64 get_monotonic_coarse64(void)
 
 	return now;
 }
+EXPORT_SYMBOL(get_monotonic_coarse64);
 
 /*
  * Must hold jiffies_lock