mlxsw: spectrum_router: Only perform atomic nexthop bucket replacement when requested

When cleared, the 'force' parameter in nexthop bucket replacement
notifications indicates that a driver should try to perform an atomic
replacement. Meaning, only update the contents of the bucket if it is
inactive.

Since mlxsw only queries buckets' activity once every second, there is
no point in trying an atomic replacement if the idle timer interval is
smaller than 1 second.

Currently, mlxsw ignores the original value of 'force' and will always
try an atomic replacement if the idle timer is not smaller than 1
second.

Fix this by taking the original value of 'force' into account and never
promoting a non-atomic replacement to an atomic one.

Fixes: 617a77f0

 ("mlxsw: spectrum_router: Add nexthop bucket replacement support")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>