[POWERPC] 8xx: powerpc port of core CPM PIC

This covers common CPM access functions, CPM interrupt controller code,
micropatch and a few compatibility things to kee the same driver base
working with arch/ppc. This version is refined with all the comments
(mostly PIC-related) addressed.

Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>