net/iavf: fix RSS protocol field selector

net/iavf: fix RSS protocol field selector

When VFs configure the rss rule by virtchnl, it need to set bit mask
into the field selector for the protocol, then PF got the configure
massage and parse the field selector to the corresponding protocol
field.

Fixes: 7be10c3004be ("net/iavf: add RSS configuration for VF")
Cc: stable@dpdk.org
Signed-off-by: Jeff Guo <jia.guo@intel.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>
Tested-by: Zhiwei He <zhiwei.he@intel.com>