target/i386: Fix wrong count setting

The previous patch used wrong count setting with index value, which got wrong
value from CPUID(EAX=12,ECX=0):EAX. So the SGX1 instruction can't be exposed
to VM and the SGX decice can't work in VM.

Fixes: d19d6ffa0710 ("target/i386: introduce helper to access supported CPUID")

Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220530131834.1222801-1-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.c

@@ -5559,7 +5559,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
          * supports.  Features can be further restricted by userspace, but not
          * made more permissive.
          */
-        x86_cpu_get_supported_cpuid(0x12, index, eax, ebx, ecx, edx);
+        x86_cpu_get_supported_cpuid(0x12, count, eax, ebx, ecx, edx);
 
         if (count == 0) {
             *eax &= env->features[FEAT_SGX_12_0_EAX];