h8300: include: asm: add "vga.h" in Kbuild

Need add "vga.h" in Kbuild, or can not pass compiling, the related error is:

CC drivers/tty/tty_io.o
In file included from include/linux/selection.h:11:0,

                   from drivers/tty/tty_io.c:103:
  include/linux/vt_buffer.h:18:21: fatal error: asm/vga.h: No such file or directory
   #include <asm/vga.h>
                       ^

---
 arch/h8300/include/asm/Kbuild |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

index 8ada3cf..f10523e 100644
@@ -5,4 +5,5 @@ generic-y += linkage.h
 generic-y += mmu.h
 generic-y += module.h
 generic-y += trace_clock.h
+generic-y += vga.h
 generic-y += xor.h

1.7.7.6