test: Rename unit-test flags

The UT_TESTF_ macros read as 'unit test test flags' which is not right.
Rename to UTF ('unit test flags').

This has the benefit of being shorter, which helps keep UNIT_TEST()
declarations on a single line.

Give the enum a name and reference it from the UNIT_TEST() macros while
we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/cmd/exit.c b/test/cmd/exit.c
index d310ec8..d4aac0f 100644
--- a/test/cmd/exit.c
+++ b/test/cmd/exit.c
@@ -122,7 +122,7 @@
 	return 0;
 }
 
-EXIT_TEST(cmd_exit_test, UT_TESTF_CONSOLE_REC);
+EXIT_TEST(cmd_exit_test, UTF_CONSOLE_REC);
 
 int do_ut_exit(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
 {