fix logging: out-of-bounds check should end with user categories

To check category bounds, rather use num_cat_user, to redirect all semantically
unknown categories to DLGLOBAL.

Adjust logging_test expectations accordingly: "(d)" is now also shown.

Note: subsys is and needs to be signed, while num_cat* are unsigned. Thus for a
negative subsys, 'subsys >= num_cat_user' practically always yields true. Pay
close attention to signedness and check upper bound only for positive values.

Change-Id: I4a952b759f30d90fbfb81fedcfc56a8092ea18c1
diff --git a/tests/logging/logging_test.err b/tests/logging/logging_test.err
index f4e9c1f..4527d83 100644
--- a/tests/logging/logging_test.err
+++ b/tests/logging/logging_test.err
@@ -4,4 +4,5 @@
 DLGLOBAL You should see this on DLGLOBAL (a)
 DLGLOBAL You should see this on DLGLOBAL (b)
 DLGLOBAL You should see this on DLGLOBAL (c)
+DLGLOBAL You should see this on DLGLOBAL (d)
 DLGLOBAL You should see this on DLGLOBAL (e)