selftests/ftrace: Add trace_printk sample module test

Add trace_printk sample module test. This requires to
enable trace_printk.ko module for test.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

tools/testing/selftests/ftrace/test.d/event/trace_printk.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Test trace_printk from module
+
+rmmod trace-printk ||:
+if ! modprobe trace-printk ; then
+  echo "No trace-printk sample module - please make CONFIG_SAMPLE_TRACE_PRINTK=m"
+  exit_unresolved;
+fi
+
+echo "Waiting for irq work"
+sleep 1
+
+grep -q ": This .* trace_bputs" trace
+grep -q ": This .* trace_puts" trace
+grep -q ": This .* trace_bprintk" trace
+grep -q ": This .* trace_printk" trace
+
+grep -q ": (irq) .* trace_bputs" trace
+grep -q ": (irq) .* trace_puts" trace
+grep -q ": (irq) .* trace_bprintk" trace
+grep -q ": (irq) .* trace_printk" trace
+
+grep -q "This is a %s that will use trace_bprintk" printk_formats
+grep -q "(irq) This is a static string that will use trace_bputs" printk_formats
+
+rmmod trace-printk ||: