target/ppc: cpu_init: Avoid nested SPR register functions

target/ppc: cpu_init: Avoid nested SPR register functions

Make sure that every register_*_sprs function only has calls to
spr_register* to register individual SPRs. Do not allow nesting. This
makes the code easier to follow and a look at init_proc_* should
suffice to know what SPRs a CPU has.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20220216162426.1885923-6-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>