When used ROUNDED_DIV(a,b), if a is unsigned integer zero, it's
will lead to an underflow issue(it called unsigned integer
wrapping).

Fixes #8062
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Mengye Lv <mengyelv@tencent.com>
Signed-off-by: Jun Zhao <barryjzhao@tencent.com>