ppc: Avoid a warning with the next patch

When the code is moved together by the next patch, compiler
detects a possible uninitialized variable use. Avoid the warning
by initializing the variables.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NAlexander Graf <agraf@suse.de>

target-ppc/mmu_helper.c

@@ -89,7 +89,7 @@ void helper_store_slb(CPUPPCState *env, target_ulong rb, target_ulong rs)
 
 target_ulong helper_load_slb_esid(CPUPPCState *env, target_ulong rb)
 {
-    target_ulong rt;
+    target_ulong rt = 0;
 
     if (ppc_load_slb_esid(env, rb, &rt) < 0) {
         helper_raise_exception_err(env, POWERPC_EXCP_PROGRAM,
@@ -100,7 +100,7 @@ target_ulong helper_load_slb_esid(CPUPPCState *env, target_ulong rb)
 
 target_ulong helper_load_slb_vsid(CPUPPCState *env, target_ulong rb)
 {
-    target_ulong rt;
+    target_ulong rt = 0;
 
     if (ppc_load_slb_vsid(env, rb, &rt) < 0) {
         helper_raise_exception_err(env, POWERPC_EXCP_PROGRAM,