target/ppc: Merge cpu_ppc_set_vhyp() with cpu_ppc_set_papr()

target/ppc: Merge cpu_ppc_set_vhyp() with cpu_ppc_set_papr()

cpu_ppc_set_papr() sets up various aspects of CPU state for use with PAPR
paravirtualized guests.  However, it doesn't set the virtual hypervisor,
so callers must also call cpu_ppc_set_vhyp() so that PAPR hypercalls are
handled properly.  This is a bit silly, so fold setting the virtual
hypervisor into cpu_ppc_set_papr().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>