target-ppc: Disentangle hash mmu versions of cpu_get_phys_page_debug()

target-ppc: Disentangle hash mmu versions of cpu_get_phys_page_debug()

cpu_get_phys_page_debug() is a trivial wrapper around
get_physical_address().  But even the signature of
get_physical_address() has some things we'd like to clean up on a
per-mmu basis, so this patch moves the test on mmu model out to
cpu_get_phys_page_debug(), moving the version for 64-bit hash MMUs out
to mmu-hash64.c and the version for 32-bit hash MMUs to mmu-hash32.c

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>