scripts: coccicheck: Use /usr/bin/env

If bash is not located under /bin, coccicheck fails to run.  In the real
world, this happens for instance when NixOS is used in the host.  Instead,
use /usr/bin/env to locate the executable binary for bash.
Signed-off-by: NJarkko Sakkinen <jarkko@kernel.org>
Tested-by: NDeepak R Varma <drv@mailo.com>
Signed-off-by: NJulia Lawall <Julia.Lawall@inria.fr>

scripts/coccicheck

-#!/bin/bash
+#!/usr/bin/env bash
 # SPDX-License-Identifier: GPL-2.0
 # Linux kernel coccicheck
 #