[POWERPC] Kill off the PTE_FMT macro

32-bit powerpc uses a PTE_FMT macro to handle printk() formatting of
PTE entries (which can vary in type and size).  Apparently there was a
good reason for it once, but with current compilers it's simpler just
to workaround the variation with a cast in the printk() itself
(there's only one use).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>