sit: use min

Opportunity for min()

Generated by: scripts/coccinelle/misc/minmax.cocci

CC: Denis Efremov <efremov@linux.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>