commit acc14694 upstream.

Make the divisor signed as DIV_ROUND_CLOSEST is undefined for negative
dividends when the divisor is unsigned.
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>