scripts: Allow use of bash outside of /bin

Even though bash is commonly available as /bin/bash there are
exceptions (e.g NixOS). This commit allow the use of the scripts in my
environment and is generic.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>

boards/x86/common/scripts/build_grub.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # Originally from the Galileo port in contiki
 # https://github.com/otcshare/contiki-x86

scripts/checkpatch/check_known_checkpatch_issues.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 #
 # Copyright (c) 2015 Intel Corporation.

scripts/checkpatch/maintainer-checkpatch.bash

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 #
 # Copyright (c) 2015 Wind River Systems, Inc.

scripts/checkpatch/timestamp

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 #
 # Copyright (c) 2015 Wind River Systems, Inc.

scripts/coccicheck

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # SPDX-License-Identifier: GPL-2.0
 #
 

tests/net/all/check_net_options.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Copyright (c) 2019 Intel Corporation.
 #