ldlinux: Move DISPLAY file handling out of the core

ldlinux: Move DISPLAY file handling out of the core

The code that handles the DISPLAY directive was writing directly to
the BIOS VGA page with __intcall(0x10). This caused corruption
problems on the screen because the ansi library code was also writing
to the screen.

The correct way to fix this is to always use the ansi library code
(via printf()) instead of going behind its back and using separate
code paths to write to the screen.

Reported-by: Ady <ady-sf@hotmail.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>