AP: Store STA supported operating classes information

This makes hostapd track Supported Operating Classes information from
the associated STAs. The stored information is available through the STA
control interface command (supp_op_classes row) as a hexdump of the
Supported Operating Classes element starting from the Length field. This
information can be used as input to BSS transition management and
channel switching decisions.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/ap/sta_info.h

@@ -190,6 +190,9 @@ struct sta_info {
 		       * enum mbo_cellular_capa values */
 	struct mbo_non_pref_chan_info *non_pref_chan;
 #endif /* CONFIG_MBO */
+
+	u8 *supp_op_classes; /* Supported Operating Classes element, if
+			      * received, starting from the Length field */
 };