[PATCH] ppc32 8xx: Added setbitsXX/clrbitsXX macro for read-modify-write operations

This adds setbitsXX/clrbitsXX macro for read-modify-write operations
and converts the 8xx core and drivers to use them.

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