test: Fix test_pinmux to run in parallel

At present test_pinmux_status() assumes that test_pinmux_dev() has run
beforehand. Drop this assumption so we can run the tests in parallel.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/test_pinmux.py b/test/py/tests/test_pinmux.py
index b3ae2ab..794994e 100644
--- a/test/py/tests/test_pinmux.py
+++ b/test/py/tests/test_pinmux.py
@@ -68,6 +68,7 @@
 def test_pinmux_status(u_boot_console):
     """Test that 'pinmux status' displays selected pincontroller's pin
     muxing descriptions."""
+    u_boot_console.run_command('pinmux dev pinctrl')
     output = u_boot_console.run_command('pinmux status')
 
     assert (not 'pinctrl-gpio:' in output)