gdiplus: Use BOOL type where appropriate

[Vincent Povirk]

 On Sat, Mar 15, 2014 at 9:44 AM, Frédéric Delanoy
<frederic.delanoy at gmail.com> wrote:
> -    rotate_90 = type&1;
> +    rotate_90 = (type & 1) != 0;
>      flip_x = (type&6) == 2 || (type&6) == 4;
>      flip_y = (type&3) == 1 || (type&3) == 2;

If you must change the style, I prefer (type&1) == 1 here, as it has
fewer negatives and matches the lines after it.