[POWERPC] EEH: Add clarifying messages.

There are multiple code patchs tht resuls in a "permanent
failure"; when examining rare events, it can be hard to see
which was taken. This patch adds printk's to assist.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>