kvm: Drop return values from kvm_arch_pre/post_run

We do not check them, and the only arch with non-empty implementations
always returns 0 (this is also true for qemu-kvm).

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
CC: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 93ecc57..bd4012a 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -256,14 +256,12 @@
     return 0;
 }
 
-int kvm_arch_post_run(CPUState *env, struct kvm_run *run)
+void kvm_arch_post_run(CPUState *env, struct kvm_run *run)
 {
-    return 0;
 }
 
-int kvm_arch_process_irqchip_events(CPUState *env)
+void kvm_arch_process_irqchip_events(CPUState *env)
 {
-    return 0;
 }
 
 static int kvmppc_handle_halt(CPUState *env)