i2c: Fix Kontron PLD prescaler calculation

Add some necessary braces that have been removed during driver cleanup.
This fixes the I2C prescaler calculation.
Signed-off-by: Michael Brunner <michael.brunner@kontron.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-kempld.c

@@ -246,9 +246,9 @@ static void kempld_i2c_device_init(struct kempld_i2c_data *i2c)
 		bus_frequency = KEMPLD_I2C_FREQ_MAX;
 
 	if (pld->info.spec_major == 1)
-		prescale = pld->pld_clock / bus_frequency * 5 - 1000;
+		prescale = pld->pld_clock / (bus_frequency * 5) - 1000;
 	else
-		prescale = pld->pld_clock / bus_frequency * 4 - 3000;
+		prescale = pld->pld_clock / (bus_frequency * 4) - 3000;
 
 	if (prescale < 0)
 		prescale = 0;