Invalid values may overflow later, leading to undefined behaviour when
multiplied by 60 to get the amount of seconds.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>