usb: gadget: f_acm: remove empty function

The significant part of this function was removed in 90f79768 ("USB:
Remove unsupported usb gadget drivers"). I would move this to function
bind time but I don't see the point in moving an empty function.
Therefore bye bye.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/gadget/f_acm.c

@@ -711,13 +711,6 @@ acm_unbind(struct usb_configuration *c, struct usb_function *f)
 	kfree(acm);
 }
 
-/* Some controllers can't support CDC ACM ... */
-static inline bool can_support_cdc(struct usb_configuration *c)
-{
-	/* everything else is *probably* fine ... */
-	return true;
-}
-
 /**
  * acm_bind_config - add a CDC ACM function to a configuration
  * @c: the configuration to support the CDC ACM instance
@@ -735,9 +728,6 @@ int acm_bind_config(struct usb_configuration *c, u8 port_num)
 	struct f_acm	*acm;
 	int		status;
 
-	if (!can_support_cdc(c))
-		return -EINVAL;
-
 	/* REVISIT might want instance-specific strings to help
 	 * distinguish instances ...
 	 */