vxlan: do not age static remote mac entries

[ Upstream commit efb5f68f32995c146944a9d4257c3cf8eae2c4a1 ]

Mac aging is applicable only for dynamically learnt remote mac
entries. Check for user configured static remote mac entries
and skip aging.

Signed-off-by: Balakrishnan Raman <ramanb@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>