target/i386/cpu.h: declare TCG_GUEST_DEFAULT_MO

This suppresses the incorrect warning when forcing MTTCG for x86
guests on x86 hosts. A future patch will still warn when
TARGET_SUPPORT_MTTCG hasn't been defined for the guest (which is still
pending for x86).
Reported-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Reviewed-by: NEduardo Habkost <ehabkost@redhat.com>
Acked-by: NEduardo Habkost <ehabkost@redhat.com>

target/i386/cpu.h

@@ -30,6 +30,9 @@
 #define TARGET_LONG_BITS 32
 #endif
 
+/* The x86 has a strong memory model with some store-after-load re-ordering */
+#define TCG_GUEST_DEFAULT_MO      (TCG_MO_ALL & ~TCG_MO_ST_LD)
+
 /* Maximum instruction code size */
 #define TARGET_MAX_INSN_SIZE 16