target-ppc: Fix warnings from Sparse

Sparse report:

target-ppc/mmu-hash64.c:353:9: warning: returning void-valued expression
target-ppc/mmu-hash64.c:620:9: warning: returning void-valued expression

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

target-ppc/mmu-hash64.c

diff --git a/target-ppc/mmu-hash64.c b/target-ppc/mmu-hash64.c
index 971751f..7df6ede 100644
--- a/target-ppc/mmu-hash64.c
+++ b/target-ppc/mmu-hash64.c
@@ -350,7 +350,7 @@
 void ppc_hash64_stop_access(uint64_t token)
 {
     if (kvmppc_kern_htab) {
-        return kvmppc_hash64_free_pteg(token);
+        kvmppc_hash64_free_pteg(token);
     }
 }
 
@@ -632,7 +632,8 @@
     CPUState *cs = CPU(ppc_env_get_cpu(env));
 
     if (kvmppc_kern_htab) {
-        return kvmppc_hash64_write_pte(env, pte_index, pte0, pte1);
+        kvmppc_hash64_write_pte(env, pte_index, pte0, pte1);
+        return;
     }
 
     pte_index *= HASH_PTE_SIZE_64;