tests: add test to read all debugfs files

Catches a bunch of forcewake warnings on snb+

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

tests/debugfs_reader

@@ -0,0 +1,27 @@
+#!/bin/sh
+
+if [ -d /debug/dri ] ; then
+	debugfs_path=/debug_dri
+fi
+
+if [ -d /sys/kernel/debug/dri ] ; then
+	debugfs_path=/sys/kernel/debug/dri
+fi
+
+i915_path=x
+for dir in `ls $debugfs_path` ; do
+	if [ -f $debugfs_path/$dir/i915_error_state ] ; then
+		i915_path=$debugfs_path/$dir
+		break
+	fi
+done
+
+if [ $i915_path = "x" ] ; then
+	echo i915 debugfs path not found.
+	exit 1
+fi
+
+# read everything we can
+cat $i915_path/* >& /dev/null
+
+exit 0