usb: typec: Comment correction for typec_partner_register_altmode

typec_register_altmode returns ERR_PTR on failure.
Signed-off-by: Kyle Tso <kyletso@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200714033453.4044482-2-kyletso@google.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/class.c

@@ -580,7 +580,7 @@ EXPORT_SYMBOL_GPL(typec_partner_set_identity);
  * SVID listed in response to Discover Modes command need to be listed in an
  * array in @desc.
  *
- * Returns handle to the alternate mode on success or NULL on failure.
+ * Returns handle to the alternate mode on success or ERR_PTR on failure.
  */
 struct typec_altmode *
 typec_partner_register_altmode(struct typec_partner *partner,