selftests: do not require bash to run bpf tests

Nothing in this minimal script seems to require bash. We often run these
tests on embedded devices where the only shell available is the busybox
ash. Use sh instead.
Signed-off-by: NRolf Eike Beer <eb@emlix.com>
Cc: stable@vger.kernel.org
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/bpf/test_kmod.sh

-#!/bin/bash
+#!/bin/sh
 
 SRC_TREE=../../../../