test/py: Shorten u_boot_console

This fixture name is quite long and results in lots of verbose code.
We know this is U-Boot so the 'u_boot_' part is not necessary.

But it is also a bit of a misnomer, since it provides access to all the
information available to tests. It is not just the console.

It would be too confusing to use con as it would be confused with
config and it is probably too short.

So shorten it to 'ubman'.

Signed-off-by: Simon Glass <sjg@chromium.org>
Link: https://lore.kernel.org/u-boot/CAFLszTgPa4aT_J9h9pqeTtLCVn4x2JvLWRcWRD8NaN3uoSAtyA@mail.gmail.com/
diff --git a/test/py/tests/test_optee_rpmb.py b/test/py/tests/test_optee_rpmb.py
index 8a081b5..d20d4bc 100644
--- a/test/py/tests/test_optee_rpmb.py
+++ b/test/py/tests/test_optee_rpmb.py
@@ -10,11 +10,11 @@
 import u_boot_utils as util
 
 @pytest.mark.buildconfigspec('cmd_optee_rpmb')
-def test_optee_rpmb_read_write(u_boot_console):
+def test_optee_rpmb_read_write(ubman):
     """Test OP-TEE RPMB cmd read/write
     """
-    response = u_boot_console.run_command('optee_rpmb write_pvalue test_variable test_value')
+    response = ubman.run_command('optee_rpmb write_pvalue test_variable test_value')
     assert response == 'Wrote 11 bytes'
 
-    response = u_boot_console.run_command('optee_rpmb read_pvalue test_variable 11')
-    assert response == 'Read 11 bytes, value = test_value'
\ No newline at end of file
+    response = ubman.run_command('optee_rpmb read_pvalue test_variable 11')
+    assert response == 'Read 11 bytes, value = test_value'