gallium/tools: do not hardcode bash location

It is not guaranteed to be in /bin

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Andreas Boll <andreas.boll.dev@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

src/gallium/tools/addr2line.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # This script processes symbols output by Gallium using glibc to human-readable function names
 
 lastbin=

src/gallium/tools/trace/tracediff.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 ##########################################################################
 #
 # Copyright 2011 Jose Fonseca