Switch to using the Power ISA defined PTE format when we have a 64-bit
PTE. This makes the code handling between fsl-booke and book3e-64
similiar for TLB faults.
Additionally this lets use take advantage of the page size encodings and
full permissions that the HW PTE defines.
Also defined _PMD_PRESENT, _PMD_PRESENT_MASK, and _PMD_BAD since the
32-bit ppc arch code expects them.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>