x86/cpu: use FeatureWordArray to define filtered_features

Use the same definition as features/user_features in CPUX86State.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190620023746.9869-1-richardw.yang@linux.intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

target/i386/cpu.h

@@ -1440,7 +1440,7 @@ struct X86CPU {
     } mwait;
 
     /* Features that were filtered out because of missing host capabilities */
-    uint32_t filtered_features[FEATURE_WORDS];
+    FeatureWordArray filtered_features;
 
     /* Enable PMU CPUID bits. This can't be enabled by default yet because
      * it doesn't have ABI stability guarantees, as it passes all PMU CPUID