s390: use two more generic header files

I missed at least these two header files where we can make use of the
generic ones.  vga.h is another one, however that is already addressed
by a patch from Jiri Slaby.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>