powerpc/64s: Machine check print NIP

Print the faulting address of the machine check that may help with
debugging. The effective address reported can be a target memory address
rather than the faulting instruction address.

Fix up a dangling bracket while here.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>