Ralue pack function needs to set op, otherwise it is 0 for add always.

Fixes: d5a1c749 ("mlxsw: reg: Add Router Algorithmic LPM Unicast Entry Register definition")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>