m68k: Add missing I/O macros {in,out}{w,l}_p() for !CONFIG_ISA

On m68k, I/O macros like inb() outw() etc. are only defined to
something useful if CONFIG_ISA is set; dummies are in place if
not, but four macros were missing from the !CONFIG_ISA case.
Adding these makes some drivers, such as speakup, compile again.

Signed-off-by: Thorsten Glaser <tg@debian.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>