Remove print_error and use normal println in exception handlers

(cherry picked from commit 9b83b2853e)

src/vga_buffer.rs

@@ -43,18 +43,6 @@ pub fn clear_screen() {
     }
 }
 
-pub unsafe fn print_error(fmt: fmt::Arguments) {
-    use core::fmt::Write;
-
-    let mut writer = Writer {
-        column_position: 0,
-        color_code: ColorCode::new(Color::Red, Color::Black),
-        buffer: Unique::new(0xb8000 as *mut _),
-    };
-    writer.new_line();
-    writer.write_fmt(fmt);
-}
-
 #[allow(dead_code)]
 #[derive(Debug, Clone, Copy)]
 #[repr(u8)]