target/s390x/cpu_models: Use 'first_cpu' in s390_get_feat_block()

We already have a global 'first_cpu' variable storing a pointer
to the first CPU, no need to use a static one.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231030093150.65297-1-philmd@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

target/s390x/cpu_models.c

@@ -196,11 +196,7 @@ uint32_t s390_get_ibc_val(void)
 
 void s390_get_feat_block(S390FeatType type, uint8_t *data)
 {
-    static S390CPU *cpu;
-
-    if (!cpu) {
-        cpu = S390_CPU(qemu_get_cpu(0));
-    }
+    S390CPU *cpu = S390_CPU(first_cpu);
 
     if (!cpu || !cpu->model) {
         return;