PPC: KVM: fix "set one register"

Due to missing @one_reg_id assignment in _spr_register(),
the kvm_get_one_reg/kvm_set_one_reg API has never really been working.

This reenables the API by assigning the @one_reg_id field in the SPR
descriptor.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

target-ppc/translate_init.c

diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index a8987d4..80f225a 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -628,6 +628,9 @@
     spr->oea_read = oea_read;
     spr->oea_write = oea_write;
 #endif
+#if defined(CONFIG_KVM)
+    spr->one_reg_id = one_reg_id,
+#endif
     env->spr[num] = initial_value;
 }