x86/cpu: Use max host physical address if -cpu max option is applied

QEMU option -cpu max(max_features) means "Enables all features supported by
the accelerator in the current host", this looks true for all the features
except guest max physical address width, so add this patch to enable it.

Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
Message-Id: <20210113090430.26394-1-weijiang.yang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.c

@@ -4319,6 +4319,7 @@ static void max_x86_cpu_initfn(Object *obj)
         if (lmce_supported()) {
             object_property_set_bool(OBJECT(cpu), "lmce", true, &error_abort);
         }
+        object_property_set_bool(OBJECT(cpu), "host-phys-bits", true, &error_abort);
     } else {
         object_property_set_str(OBJECT(cpu), "vendor", CPUID_VENDOR_AMD,
                                 &error_abort);