Function init_panic_fb_globals 

pub fn init_panic_fb_globals(
    addr: u64,
    w: usize,
    h: usize,
    pitch: usize,
    bpp: u16,
    red_shift: u8,
    green_shift: u8,
    blue_shift: u8,
)

Initialise the panic-screen framebuffer globals. Must be called once from vga::init() after configure() succeeds.