coccinelle: Add rules to find str_up_down() replacements

Add rules for finding places where str_up_down() can be used.
This currently finds over 20 locations.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/r/20240725101841.574-2-michal.wajdeczko@intel.comSigned-off-by: Kees Cook <kees@kernel.org>

scripts/coccinelle/api/string_choices.cocci

@@ -39,3 +39,26 @@ e << str_plural_r.E;
 @@
 
 coccilib.report.print_report(p[0], "opportunity for str_plural(%s)" % e)
+
+@str_up_down depends on patch@
+expression E;
+@@
+(
+-	((E) ? "up" : "down")
++	str_up_down(E)
+)
+
+@str_up_down_r depends on !patch exists@
+expression E;
+position P;
+@@
+(
+*	((E@P) ? "up" : "down")
+)
+
+@script:python depends on report@
+p << str_up_down_r.P;
+e << str_up_down_r.E;
+@@
+
+coccilib.report.print_report(p[0], "opportunity for str_up_down(%s)" % e)