usb: typec: Check for ops->exit instead of ops->enter in altmode_exit

typec_altmode_exit checks if ops->enter is not NULL but then calls
ops->exit a few lines below. Fix that and check for the function
pointer it's about to call instead.

Fixes: 8a37d87d72f0 ("usb: typec: Bus type for alternate modes")
Signed-off-by: Sven Peter <[e-mail]>
Reviewed-by: Heikki Krogerus <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/typec/bus.c

···
 	if (!adev || !adev->active)
 		return 0;
 
-	if (!pdev->ops || !pdev->ops->enter)
+	if (!pdev->ops || !pdev->ops->exit)
 		return -EOPNOTSUPP;
 
 	/* Moving to USB Safe State */