This patch adds workaround for PPC 440GX erratum 440_43. According to
this erratum spurious MachineChecks (caused by L1 cache parity) can
happen during DataTLB miss processing. We disable L1 cache parity
checking for 440GX rev.C and rev.F

Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>