Fix wpa_supplicant build error with IEEE8021X_EAPOL unset

Add missing inline stubs for newly added functions.

Fixes: 3459381dd260 ("External persistent storage for PMKSA cache entries")
Signed-off-by: Felix Fietkau <nbd@nbd.name>

src/rsn_supp/pmksa_cache.h

@@ -107,6 +107,19 @@ static inline int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf,
 	return -1;
 }
 
+static inline struct rsn_pmksa_cache_entry *
+pmksa_cache_head(struct rsn_pmksa_cache *pmksa)
+{
+	return NULL;
+}
+
+static inline struct rsn_pmksa_cache_entry *
+pmksa_cache_add_entry(struct rsn_pmksa_cache *pmksa,
+		      struct rsn_pmksa_cache_entry *entry)
+{
+	return NULL;
+}
+
 static inline struct rsn_pmksa_cache_entry *
 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
 		const u8 *pmkid, const u8 *kck, size_t kck_len,