time: remove obsolete declaration

The function, timekeeping_leap_insert, was removed in commit
6b43ae8a619d17c4935c3320d2ef9e92bdeed05d

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
1 file changed