target/arm: Check aa32_pan in take_aarch32_exception(), not aa64_pan

In take_aarch32_exception(), we know we are dealing with a CPU that
has AArch32, so the right isar_feature test is aa32_pan, not aa64_pan.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Message-id: 20200214175116.9164-3-peter.maydell@linaro.org

target/arm/helper.c

@@ -8858,7 +8858,7 @@ static void take_aarch32_exception(CPUARMState *env, int new_mode,
         env->elr_el[2] = env->regs[15];
     } else {
         /* CPSR.PAN is normally preserved preserved unless...  */
-        if (cpu_isar_feature(aa64_pan, env_archcpu(env))) {
+        if (cpu_isar_feature(aa32_pan, env_archcpu(env))) {
             switch (new_el) {
             case 3:
                 if (!arm_is_secure_below_el3(env)) {