target/ppc: Change partition-scope translate interface

target/ppc: Change partition-scope translate interface

Rather than always performing partition scope page table translation
with access type of 0 (MMU_DATA_LOAD), pass through the processor
access type which first initiated the translation sequence. Process-
scoped page table loads are then set to MMU_DATA_LOAD access type in
the xlate function.

This will allow more information to be passed to the exception
handler in the next patch.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>