lib/string_choices: Add str_plural() helper

Add str_plural() helper to replace existing open implementations
used by many drivers and help improve future user facing messages.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://lore.kernel.org/r/20240214165015.1656-1-michal.wajdeczko@intel.com
Signed-off-by: Kees Cook <keescook@chromium.org>

include/linux/string_choices.h

@@ -42,4 +42,15 @@ static inline const char *str_yes_no(bool v)
 	return v ? "yes" : "no";
 }
 
+/**
+ * str_plural - Return the simple pluralization based on English counts
+ * @num: Number used for deciding pluralization
+ *
+ * If @num is 1, returns empty string, otherwise returns "s".
+ */
+static inline const char *str_plural(size_t num)
+{
+	return num == 1 ? "" : "s";
+}
+
 #endif