powerpc/32: %pF is only for function pointers

Use %pS for actual addresses, otherwise you'll get bad output
on arches like ppc64 where %pF expects a function descriptor.  Even on
other architectures, refrain from setting a bad example that people
copy.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>