Respect rotation in partial refresh boundary checks

When rotating the image and performing partial updates on it,
those partial updates partly never appeared or were cut off.
Since with rotating, var_screen_info.x/yres update accordingly,
those are now used for boundary checks instead.

Image of attempted partial updates:
https://transfer.cosmos-ink.net/T6zFn/20200805_183246_lq.jpg

src/framebuffer/refresh.rs

@@ -79,8 +79,8 @@ impl<'a> framebuffer::FramebufferRefresh for core::Framebuffer<'a> {
         let mut update_region = region.to_owned();
 
         // No accounting for this, out of bounds, entirely ignored
-        if update_region.left >= u32::from(common::DISPLAYWIDTH)
-            || update_region.top >= u32::from(common::DISPLAYHEIGHT)
+        if update_region.left >= u32::from(self.var_screen_info.xres)
+            || update_region.top >= u32::from(self.var_screen_info.yres)
         {
             return 0;
         }
@@ -94,14 +94,14 @@ impl<'a> framebuffer::FramebufferRefresh for core::Framebuffer<'a> {
 
         // Dont try to refresh OOB horizontally
         let max_x = update_region.left + update_region.width;
-        if max_x > u32::from(common::DISPLAYWIDTH) {
-            update_region.width -= max_x - u32::from(common::DISPLAYWIDTH);
+        if max_x > u32::from(self.var_screen_info.xres) {
+            update_region.width -= max_x - u32::from(self.var_screen_info.xres);
         }
 
         // Dont try to refresh OOB vertically
         let max_y = update_region.top + update_region.height;
-        if max_y > u32::from(common::DISPLAYHEIGHT) {
-            update_region.height -= max_y - u32::from(common::DISPLAYHEIGHT);
+        if max_y > u32::from(self.var_screen_info.yres) {
+            update_region.height -= max_y - u32::from(self.var_screen_info.yres);
         }
 
         let update_mode = if force_full_refresh {