usb: typec: thunderbolt: Remove IS_ERR check for plug

[ Upstream commit 9682c35 ]

Fixes these Smatch static checker warnings:
drivers/usb/typec/altmodes/thunderbolt.c:354 tbt_ready() warn: 'plug' is not an error pointer

Fixes: 100e257 ("usb: typec: Add driver for Thunderbolt 3 Alternate Mode")
Signed-off-by: Benson Leung <bleung@chromium.org>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/Z5PstnlA52Z1F2SU@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/usb/typec/altmodes/thunderbolt.c

@@ -351,10 +351,10 @@ static bool tbt_ready(struct typec_altmode *alt)
 	 */
 	for (int i = 0; i < TYPEC_PLUG_SOP_PP + 1; i++) {
 		plug = typec_altmode_get_plug(tbt->alt, i);
-		if (IS_ERR(plug))
+		if (!plug)
 			continue;
 
-		if (!plug || plug->svid != USB_TYPEC_TBT_SID)
+		if (plug->svid != USB_TYPEC_TBT_SID)
 			break;
 
 		plug->desc = "Thunderbolt3";