ath6kl: add firmware IE for maximum number of vifs

Not all firmwares support multiple vifs and we need to read the limit from
the firmware image.
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath6kl/core.h

@@ -71,6 +71,7 @@ enum ath6kl_fw_ie_type {
 	ATH6KL_FW_IE_CAPABILITIES = 6,
 	ATH6KL_FW_IE_PATCH_ADDR = 7,
 	ATH6KL_FW_IE_BOARD_ADDR = 8,
+	ATH6KL_FW_IE_VIF_MAX = 9,
 };
 
 enum ath6kl_fw_capability {
@@ -502,7 +503,7 @@ struct ath6kl {
 	/* Lock to avoid race in vif_list entries among add/del/traverse */
 	spinlock_t list_lock;
 	u8 num_vif;
-	int vif_max;
+	unsigned int vif_max;
 	u8 max_norm_iface;
 	u8 avail_idx_map;
 	spinlock_t lock;

drivers/net/wireless/ath/ath6kl/init.c

@@ -963,6 +963,17 @@ static int ath6kl_fetch_fw_api2(struct ath6kl *ar)
 				   "found board address ie 0x%x\n",
 				   ar->hw.board_addr);
 			break;
+		case ATH6KL_FW_IE_VIF_MAX:
+			if (ie_len != sizeof(*val))
+				break;
+
+			val = (__le32 *) data;
+			ar->vif_max = min_t(unsigned int, le32_to_cpup(val),
+					    ATH6KL_VIF_MAX);
+
+			ath6kl_dbg(ATH6KL_DBG_BOOT,
+				   "found vif max ie %d\n", ar->vif_max);
+			break;
 		default:
 			ath6kl_dbg(ATH6KL_DBG_BOOT, "Unknown fw ie: %u\n",
 				   le32_to_cpup(&hdr->id));