target/ppc: Fix move-to timebase SPR access permissions

The move-to timebase registers TBU and TBL can not be read, and they
can not be written in supervisor mode on hypervisor-capable CPUs.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
1 file changed