target/arm: Fix test of TCG_OVERSIZED_GUEST

The symbol is always defined, even if to 0.  We wanted to test for
TCG_OVERSIZED_GUEST == 0.

This fixed, the #error is reached while building arm-softmmu, because
TCG_OVERSIZED_GUEST is not true (nor supposed to be true) for arm32
guest on a 32-bit host.  But that's ok, because this feature doesn't
apply to arm32.  Add an #ifdef for TARGET_AARCH64.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/arm/ptw.c

@@ -418,6 +418,7 @@ static uint64_t arm_casq_ptw(CPUARMState *env, uint64_t old_val,
                              uint64_t new_val, S1Translate *ptw,
                              ARMMMUFaultInfo *fi)
 {
+#ifdef TARGET_AARCH64
     uint64_t cur_val;
     void *host = ptw->out_host;
 
@@ -473,7 +474,7 @@ static uint64_t arm_casq_ptw(CPUARMState *env, uint64_t old_val,
      * we know that TCG_OVERSIZED_GUEST is set, which means that we are
      * running in round-robin mode and could only race with dma i/o.
      */
-#ifndef TCG_OVERSIZED_GUEST
+#if !TCG_OVERSIZED_GUEST
 # error "Unexpected configuration"
 #endif
     bool locked = qemu_mutex_iothread_locked();
@@ -497,6 +498,10 @@ static uint64_t arm_casq_ptw(CPUARMState *env, uint64_t old_val,
 #endif
 
     return cur_val;
+#else
+    /* AArch32 does not have FEAT_HADFS. */
+    g_assert_not_reached();
+#endif
 }
 
 static bool get_level1_table_address(CPUARMState *env, ARMMMUIdx mmu_idx,