clocksource: sh_tmu: Make undefined TCOR behaviour less undefined.

Avoid undocumented vague TMU behavior when zero value is set to TCOR.

This primarily fixes up issues encountered under qemu with a zero-length
period, while the hardware itself is fairly ambivalent one way or the
other.
Signed-off-by: NShin-ichiro KAWASAKI <kawasaki@juno.dti.ne.jp>
Acked-by: NMagnus Damm <damm@igel.co.jp>
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

drivers/clocksource/sh_tmu.c

@@ -161,7 +161,7 @@ static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
 	if (periodic)
 		sh_tmu_write(p, TCOR, delta);
 	else
-		sh_tmu_write(p, TCOR, 0);
+		sh_tmu_write(p, TCOR, 0xffffffff);
 
 	sh_tmu_write(p, TCNT, delta);