[ARM] 5303/1: period_cycles should be greater than 1

If period_cycles is 0, prescale becomes silly.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-pxa/pwm.c

@@ -60,7 +60,7 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
 	do_div(c, 1000000000);
 	period_cycles = c;
 
-	if (period_cycles < 0)
+	if (period_cycles < 1)
 		period_cycles = 1;
 	prescale = (period_cycles - 1) / 1024;
 	pv = period_cycles / (prescale + 1) - 1;