stat: Avoid freeing null pointer

stat: Avoid freeing null pointer

If ovals is NULL, the jump to out will free(ovals) and will trigger an error.
As the out label was only used for this condition, let's remove it and return immediately.
As out was also used as a variable name, this makes the function easier
to read and more robust.

Signed-off-by: Erwan Velu <erwanaliasr1@gmail.com>