The incorrect mask was being used when writing back to PMNC write-only-zero
bits as well as only ticking the CCNT every 64 processor cycles.  Tested on
IOP331 and PXA270, i'm still looking for XScale1 users...
Signed-off-by: Luca Rossato <l.rossato@tiscali.it>
Signed-off-by: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>