[qca-nss-sfe] Don't write L2 hdr for the non-arp interface

Some supported egress interface do not take an L2 header.
Avoiding adding one in those cases.

Change-Id: I4395884da8235145ad51dbade72fea59ee68f625
Signed-off-by: Ken Zhu <quic_guigenz@quicinc.com>
2 files changed