thunderbolt: Increase DisplayPort Connection Manager handshake timeout

It turns out that when plugging in VGA cable through USB-C to VGA/DVI
dongle the Connection Manager handshake can take longer time, at least
on Intel Titan Ridge based docks such as Dell WD91TB. This leads to
following error in the dmesg:

  thunderbolt 0000:00:0d.3: 3:10: DP tunnel activation failed, aborting

and the display stays blank (because we failed to establish the tunnel).
For this reason increase the timeout to 3s.
Reported-by: Koba Ko <koba.ko@canonical.com>
Cc: stable@vger.kernel.org
Acked-By: Yehezkel Bernat <YehezkelShB@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/tunnel.c

@@ -526,7 +526,7 @@ static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
 	 * Perform connection manager handshake between IN and OUT ports
 	 * before capabilities exchange can take place.
 	 */
-	ret = tb_dp_cm_handshake(in, out, 1500);
+	ret = tb_dp_cm_handshake(in, out, 3000);
 	if (ret)
 		return ret;