lxc: Drop useless check in live device update

Checking the new device definition makes little sense when lxc driver
does not support live device update at all.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/lxc/lxc_driver.c

@@ -4939,9 +4939,6 @@ static int lxcDomainUpdateDeviceFlags(virDomainPtr dom,
     }
 
     if (flags & VIR_DOMAIN_AFFECT_LIVE) {
-        if (virDomainDefCompatibleDevice(vm->def, dev_copy) < 0)
-            goto endjob;
-
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                        _("Unable to modify live devices"));