net/vhost: enable promiscuous and multicast by default

net/vhost: enable promiscuous and multicast by default

With this patch, the promiscuous and multicast fields are initialized as
enabled for vhost PMD by default, this allows the devices to be used
when running applications that attempt to enable promiscuous or
multicast mode.
Similar things have done for other virtual PMDs by commit f165210321c4
("drivers/net: enable promiscuous and multicast by default")

Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>