target-i386: Add "mpx" CPU feature name

Migration support for MPX is already implemented (commit
79e9ebebbf2a00c46fcedb6dc7dd5e12bbd30216), so we can add it to the list
of known feature names.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target-i386/cpu.c

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 52e335f..f4ee353 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -258,7 +258,7 @@
 
 static const char *cpuid_7_0_ebx_feature_name[] = {
     "fsgsbase", NULL, NULL, "bmi1", "hle", "avx2", NULL, "smep",
-    "bmi2", "erms", "invpcid", "rtm", NULL, NULL, NULL, NULL,
+    "bmi2", "erms", "invpcid", "rtm", NULL, NULL, "mpx", NULL,
     NULL, NULL, "rdseed", "adx", "smap", NULL, NULL, NULL,
     NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
 };