powerpc/booke: Fix a couple typos in the advanced ptrace code

Found and fixed a couple typos in the advanced ptrace patches.
(These patches are currently in benh's next tree.)
Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev list <Linuxppc-dev@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>