mwifiex: don't complain about 'unknown event id: 0x63'

Marvell folks tell me this is a debugging event that the driver doesn't
need to handle, but on 8997 w/ firmware 16.68.1.p97, I see several of
these sorts of messages at (for instance) boot time:

[   13.825848] mwifiex_pcie 0000:01:00.0: event: unknown event id: 0x63
[   14.838561] mwifiex_pcie 0000:01:00.0: event: unknown event id: 0x63
[   14.850397] mwifiex_pcie 0000:01:00.0: event: unknown event id: 0x63
[   32.529923] mwifiex_pcie 0000:01:00.0: event: unknown event id: 0x63

Let's handle this "event" with a much lower verbosity.
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/fw.h

@@ -550,6 +550,7 @@ enum mwifiex_channel_flags {
 #define EVENT_TX_DATA_PAUSE             0x00000055
 #define EVENT_EXT_SCAN_REPORT           0x00000058
 #define EVENT_RXBA_SYNC                 0x00000059
+#define EVENT_UNKNOWN_DEBUG             0x00000063
 #define EVENT_BG_SCAN_STOPPED           0x00000065
 #define EVENT_REMAIN_ON_CHAN_EXPIRED    0x0000005f
 #define EVENT_MULTI_CHAN_INFO           0x0000006a

drivers/net/wireless/marvell/mwifiex/sta_event.c

@@ -1009,6 +1009,10 @@ int mwifiex_process_sta_event(struct mwifiex_private *priv)
 					    adapter->event_skb->len -
 					    sizeof(eventcause));
 		break;
+	/* Debugging event; not used, but let's not print an ERROR for it. */
+	case EVENT_UNKNOWN_DEBUG:
+		mwifiex_dbg(adapter, EVENT, "event: debug\n");
+		break;
 	default:
 		mwifiex_dbg(adapter, ERROR, "event: unknown event id: %#x\n",
 			    eventcause);