win32: always fit to the screen on initial positioning

VO_WIN_FORCE_POS is set even if the position is not provided by the
user, so we have no choice but to always fit. We should do this
regardless, and if any issues occur in multi-monitor configurations,
they should be addressed separately.

Fixes: #15049
Fixes: e5159de811

video/out/w32_common.c

@@ -1950,7 +1950,7 @@ static void window_reconfig(struct vo_w32_state *w32, bool force)
         w32->prev_windowrc = w32->windowrc;
         w32->window_bounds_initialized = true;
         w32->win_force_pos = geo.flags & VO_WIN_FORCE_POS;
-        w32->fit_on_screen = !w32->win_force_pos;
+        w32->fit_on_screen = true;
         goto finish;
     }