devtools: fix checkpatch with dash

devtools: fix checkpatch with dash

When running checkpatch.sh, it generates the following error
on some linux distributions(like Debian) with Dash as the
default shell interpreter.
trap: SIGINT: bad trap

The fix is to replace SIGINT with INT signal, it works for
both bash and dash.

Fixes: 4bec48184e ("devtools: add checks for ABI symbol addition")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Acked-by: John McNamara <john.mcnamara@intel.com>
Tested-by: Vipin Varghese <vipin.varghese@intel.com>