[wlanstack] Increase channel read buffer size

NET-1212
Test: manual testing

Change-Id: Ic83a244aabd4e476b5b903071daf27c5318fa001
diff --git a/go/src/wlan/wlan/wlan.go b/go/src/wlan/wlan/wlan.go
index 9b9e928..86e7124 100644
--- a/go/src/wlan/wlan/wlan.go
+++ b/go/src/wlan/wlan/wlan.go
@@ -326,7 +326,7 @@
 
 		case obs&ZX_SOCKET_READABLE != 0:
 			// TODO(tkilbourn): decide on a default buffer size, and support growing the buffer as needed
-			var buf [5120]byte
+			var buf [16384]byte
 			_, _, err := c.mlmeChan.Read(buf[:], nil, 0)
 			if err != nil {
 				return nil, fmt.Errorf("error reading from channel: %v", err)