yuzu/bootmanager: Treat the resolution factor as a u32

Treating it as a u16 can result in a sign-conversion warning when
performing arithmetic with it, as u16 promotes to an int when aritmetic
is performed on it, not unsigned int.

This also makes the interface more uniform, as the layout interface now
operates on u32 across the board.

src/core/frontend/framebuffer_layout.cpp

@@ -20,7 +20,7 @@ static Common::Rectangle<T> MaxRectangle(Common::Rectangle<T> window_area,
                                 static_cast<T>(std::round(scale * screen_aspect_ratio))};
 }
 
-FramebufferLayout DefaultFrameLayout(unsigned width, unsigned height) {
+FramebufferLayout DefaultFrameLayout(u32 width, u32 height) {
     ASSERT(width > 0);
     ASSERT(height > 0);
     // The drawing code needs at least somewhat valid values for both screens
@@ -29,22 +29,23 @@ FramebufferLayout DefaultFrameLayout(unsigned width, unsigned height) {
 
     const float emulation_aspect_ratio{static_cast<float>(ScreenUndocked::Height) /
                                        ScreenUndocked::Width};
-    Common::Rectangle<unsigned> screen_window_area{0, 0, width, height};
-    Common::Rectangle<unsigned> screen = MaxRectangle(screen_window_area, emulation_aspect_ratio);
+    const auto window_aspect_ratio = static_cast<float>(height) / width;
 
-    float window_aspect_ratio = static_cast<float>(height) / width;
+    const Common::Rectangle<u32> screen_window_area{0, 0, width, height};
+    Common::Rectangle<u32> screen = MaxRectangle(screen_window_area, emulation_aspect_ratio);
 
     if (window_aspect_ratio < emulation_aspect_ratio) {
         screen = screen.TranslateX((screen_window_area.GetWidth() - screen.GetWidth()) / 2);
     } else {
         screen = screen.TranslateY((height - screen.GetHeight()) / 2);
     }
+
     res.screen = screen;
     return res;
 }
 
-FramebufferLayout FrameLayoutFromResolutionScale(u16 res_scale) {
-    int width, height;
+FramebufferLayout FrameLayoutFromResolutionScale(u32 res_scale) {
+    u32 width, height;
 
     if (Settings::values.use_docked_mode) {
         width = ScreenDocked::WidthDocked * res_scale;