hw/intc/arm_gicv3_its: Avoid maybe-uninitialized error in get_vte()

Fix when using GCC v11.4 (Ubuntu 11.4.0-1ubuntu1~22.04) with CFLAGS=-Og:

  [4/6] Compiling C object libcommon.fa.p/hw_intc_arm_gicv3_its.c.o
  FAILED: libcommon.fa.p/hw_intc_arm_gicv3_its.c.o
      inlined from ‘lookup_vte’ at hw/intc/arm_gicv3_its.c:453:9,
      inlined from ‘vmovp_callback’ at hw/intc/arm_gicv3_its.c:1039:14:
  hw/intc/arm_gicv3_its.c:347:9: error: ‘vte.rdbase’ may be used uninitialized [-Werror=maybe-uninitialized]
    347 |         trace_gicv3_its_vte_read(vpeid, vte->valid, vte->vptsize,
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    348 |                                  vte->vptaddr, vte->rdbase);
        |                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~
  hw/intc/arm_gicv3_its.c: In function ‘vmovp_callback’:
  hw/intc/arm_gicv3_its.c:1036:13: note: ‘vte’ declared here
   1036 |     VTEntry vte;
        |             ^~~

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20230831131348.69032-1-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/intc/arm_gicv3_its.c

@@ -330,23 +330,20 @@ static MemTxResult get_vte(GICv3ITSState *s, uint32_t vpeid, VTEntry *vte)
     if (entry_addr == -1) {
         /* No L2 table entry, i.e. no valid VTE, or a memory error */
         vte->valid = false;
-        goto out;
+        trace_gicv3_its_vte_read_fault(vpeid);
+        return MEMTX_OK;
     }
     vteval = address_space_ldq_le(as, entry_addr, MEMTXATTRS_UNSPECIFIED, &res);
     if (res != MEMTX_OK) {
-        goto out;
+        trace_gicv3_its_vte_read_fault(vpeid);
+        return res;
     }
     vte->valid = FIELD_EX64(vteval, VTE, VALID);
     vte->vptsize = FIELD_EX64(vteval, VTE, VPTSIZE);
     vte->vptaddr = FIELD_EX64(vteval, VTE, VPTADDR);
     vte->rdbase = FIELD_EX64(vteval, VTE, RDBASE);
-out:
-    if (res != MEMTX_OK) {
-        trace_gicv3_its_vte_read_fault(vpeid);
-    } else {
-        trace_gicv3_its_vte_read(vpeid, vte->valid, vte->vptsize,
-                                 vte->vptaddr, vte->rdbase);
-    }
+    trace_gicv3_its_vte_read(vpeid, vte->valid, vte->vptsize,
+                             vte->vptaddr, vte->rdbase);
     return res;
 }