[POWERPC] Fix STRICT_MM_TYPECHECKS

Since we don't have it active by default, the STRICT_MM_TYPECHECKS
option has bitrotted again.  This patch fixes a couple of simple build
fixes if the option is selected.  First, pud_t mustn't be defined in
page.h on 32-bit systems, because it conflicts with the version in the
generic pud-folding code.  Second, pci_32.c is missing a __pgprot()
wrapper call.  Third, a couple of PS3 files use constants of type
pgprot_t when they need the raw values, we add pgprot_val() calls to
fix this.

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