selftests: do not require bash for the generated test

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
Signed-off-by: NShuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/Makefile

@@ -90,7 +90,7 @@ ifdef INSTALL_PATH
 	done;
 
 	@# Ask all targets to emit their test scripts
-	echo "#!/bin/bash" > $(ALL_SCRIPT)
+	echo "#!/bin/sh" > $(ALL_SCRIPT)
 	echo "cd \$$(dirname \$$0)" >> $(ALL_SCRIPT)
 	echo "ROOT=\$$PWD" >> $(ALL_SCRIPT)