i386: Make arch_capabilities migratable

Now that kvm_arch_get_supported_cpuid() will only return
arch_capabilities if QEMU is able to initialize the MSR properly,
we know that the feature is safely migratable.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190125220606.4864-3-ehabkost@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

target/i386/cpu.c

@@ -1089,7 +1089,6 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             .reg = R_EDX,
         },
         .tcg_features = TCG_7_0_EDX_FEATURES,
-        .unmigratable_flags = CPUID_7_0_EDX_ARCH_CAPABILITIES,
     },
     [FEAT_8000_0007_EDX] = {
         .type = CPUID_FEATURE_WORD,