target/ppc: Move 1T segment and AMR options to PPCHash64Options

target/ppc: Move 1T segment and AMR options to PPCHash64Options

Currently env->mmu_model is a bit of an unholy mess of an enum of distinct
MMU types, with various flag bits as well.  This makes which bits of the
field should be compared pretty confusing.

Make a start on cleaning that up by moving two of the flags bits -
POWERPC_MMU_1TSEG and POWERPC_MMU_AMR - which are specific to the 64-bit
hash MMU into a new flags field in PPCHash64Options structure.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>