mx5/6 timer: Round up tick_to_time() value

Round up tick_to_time() value instead of truncating it. This avoids stopping
waits instantly for low usec values, and this generally guarantees that the code
always waits for at least the requested duration.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Stefano Babic <sbabic@denx.de>
Acked-by: Stefano Babic <sbabic@denx.de>

arch/arm/cpu/armv7/imx-common/timer.c

@@ -61,7 +61,7 @@ static inline unsigned long long tick_to_time(unsigned long long tick)
 
 static inline unsigned long long us_to_tick(unsigned long long usec)
 {
-	usec *= CLK_32KHZ;
+	usec = usec * CLK_32KHZ + 999999;
 	do_div(usec, 1000000);
 
 	return usec;