target-mips: fix compiler warnings (clang 5)

static code analyzer complain:

target/mips/helper.c:453:5: warning: Function call argument is an uninitialized value
    qemu_log_mask(CPU_LOG_MMU,
    ^~~~~~~~~~~~~~~~~~~~~~~~~~

'physical' and 'prot' are uninitialized if 'ret' is not TLBRET_MATCH.

Reported-by: Clang Static Analyzer
Signed-off-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NYongbok Kim <yongbok.kim@imgtec.com>
Signed-off-by: NYongbok Kim <yongbok.kim@imgtec.com>

target/mips/helper.c

@@ -450,10 +450,18 @@ int mips_cpu_handle_mmu_fault(CPUState *cs, vaddr address, int rw,
     access_type = ACCESS_INT;
     ret = get_physical_address(env, &physical, &prot,
                                address, rw, access_type);
-    qemu_log_mask(CPU_LOG_MMU,
-             "%s address=%" VADDR_PRIx " ret %d physical " TARGET_FMT_plx
-             " prot %d\n",
-             __func__, address, ret, physical, prot);
+    switch (ret) {
+    case TLBRET_MATCH:
+        qemu_log_mask(CPU_LOG_MMU,
+                      "%s address=%" VADDR_PRIx " physical " TARGET_FMT_plx
+                      " prot %d\n", __func__, address, physical, prot);
+        break;
+    default:
+        qemu_log_mask(CPU_LOG_MMU,
+                      "%s address=%" VADDR_PRIx " ret %d\n", __func__, address,
+                      ret);
+        break;
+    }
     if (ret == TLBRET_MATCH) {
         tlb_set_page(cs, address & TARGET_PAGE_MASK,
                      physical & TARGET_PAGE_MASK, prot | PAGE_EXEC,