Don't use -fomit-frame-pointer when building VGA bios.

Don't use -fomit-frame-pointer when building VGA bios.

The real-mode emulator that Windows 7 uses to execute the vga bios rom
becomes very confused when the code tries to dereference the stack
pointer instead of using the frame pointer, leading to corruption of
parameters passed on the stack from one function to another.

Signed-off-by: Julian Pidancet <julian.pidancet@gmail.com>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>