vgasrc: Increase debug level

You only want this information for debugging. As it also slows down the
boot considerably, as, for example, for every character of the GRUB
menu, something is sent over the serial console.

Therefore, increase the debugging level to 9.

Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>

vgasrc/vgabios.h

@@ -73,7 +73,7 @@ static inline int vga_emulate_text(void) {
 
 // Debug settings
 #define DEBUG_VGA_POST 1
-#define DEBUG_VGA_10 3
+#define DEBUG_VGA_10 9
 
 // vgabios.c
 int vga_bpp(struct vgamode_s *vmode_g);