cpus: fix wrong define name

While the configure script generates TARGET_SUPPORTS_MTTCG define, one
of the define is cpus.c is checking wrong name: TARGET_SUPPORT_MTTCG
Signed-off-by: NNikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>

cpus.c

@@ -202,7 +202,7 @@ void qemu_tcg_configure(QemuOpts *opts, Error **errp)
             } else if (use_icount) {
                 error_setg(errp, "No MTTCG when icount is enabled");
             } else {
-#ifndef TARGET_SUPPORT_MTTCG
+#ifndef TARGET_SUPPORTS_MTTCG
                 error_report("Guest not yet converted to MTTCG - "
                              "you may get unexpected results");
 #endif