test: Move POST under a renamed Testing section

Rename Unit tests to Testing, since it is a stretch to describe some of
the tests as unit tests. Move POST there as well, so it doesn't show up
by itself in the top-level menu.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

test/Kconfig

@@ -1,9 +1,4 @@
-config POST
-	bool "Power On Self Test support"
-	help
-	  See doc/README.POST for more details
-
-menu "Unit tests"
+menu "Testing"
 
 config UNIT_TEST
 	bool "Unit tests"
@@ -110,4 +105,9 @@ source "test/lib/Kconfig"
 source "test/optee/Kconfig"
 source "test/overlay/Kconfig"
 
+config POST
+	bool "Power On Self Test support"
+	help
+	  See doc/README.POST for more details
+
 endmenu