ppc/translate: Use POWERPC_MMU_64 to detect 64-bit MMU models

ppc/translate: Use POWERPC_MMU_64 to detect 64-bit MMU models

The ppc_tr_init_disas_context() function currently checks whether the
MMU is 64-bit by ANDing its model type with POWERPC_MMU_64B. This is
wrong : POWERPC_MMU_64B isn't a mask, it is the generic MMU model for
pre-PowerISA-2.03 64-bit CPUs (ie. PowerPC 970 in QEMU).

Use POWERPC_MMU_64 instead of POWERPC_MMU_64B. This should fix a
potential bug with some 32-bit CPUs for which 'need_access_type'
was mis-computed because (POWERPC_MMU_32B & POWERPC_MMU_64B)
happens to be equal to 1. The end result being a crash in
ppc_hash32_direct_store() because the access type isn't set:

        cpu_abort(cs, "ERROR: instruction should not need "
                 "address translation\n");

This doesn't change anything for 'lazy_tlb_flush' since POWERPC_MMU_32B
is checked first.

Fixes: 5f2a6254522b ("ppc: Don't set access_type on all load/stores on hash64")
Signed-off-by: Stephane Duverger <stephane.duverger@free.fr>
[groug: - extended patch to address another misuse of POWERPC_MMU_64B
        - updated title and changelog accordingly]
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20201209173536.1437351-2-groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>