i386: indicate that 'pconfig' feature was removed intentionally

pconfig feature was added in 5131dc4 and removed in 712f807.
This patch mark this feature as known to QEMU and removed by
intentinally. This follows the convention of 9ccb978 and f1a2352
dealing with 'osxsave' and 'ospke'.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20190719111222.14943-1-den@openvz.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.c

@@ -1083,7 +1083,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
             NULL, NULL, NULL, NULL,
             NULL, NULL, "md-clear", NULL,
             NULL, NULL, NULL, NULL,
-            NULL, NULL, NULL, NULL,
+            NULL, NULL, NULL /* pconfig */, NULL,
             NULL, NULL, NULL, NULL,
             NULL, NULL, "spec-ctrl", "stibp",
             NULL, "arch-capabilities", "core-capability", "ssbd",