This patch adds a marker to the exception stack frame to aid in debugging.
It's already inserted on other platforms and xmon recognizes it and
identifies exception frames when showing stack traces.
Signed-off-by: NTorez Smith  <lnxtorez@linux.vnet.ibm.com>
Signed-off-by: NDave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>