usb: cdns3: cdns3-ep0: Fix a few kernel-doc formatting issues

Fixes the following W=1 kernel build warning(s):

drivers/usb/cdns3/cdns3-ep0.c:680: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
drivers/usb/cdns3/cdns3-ep0.c:775: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
drivers/usb/cdns3/cdns3-ep0.c:868: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Cc: Peter Chen <[e-mail]>
Cc: Pawel Laszczak <[e-mail]>
Cc: Roger Quadros <[e-mail]>
Cc: Aswath Govindraju <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Pawel Jez <[e-mail]>
Cc: [e-mail]
Acked-by: Peter Chen <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/cdns3/cdns3-ep0.c

···
 }
 
 /**
- * cdns3_gadget_ep0_queue Transfer data on endpoint zero
+ * cdns3_gadget_ep0_queue - Transfer data on endpoint zero
  * @ep: pointer to endpoint zero object
  * @request: pointer to request object
  * @gfp_flags: gfp flags
···
 }
 
 /**
- * cdns3_gadget_ep_set_wedge Set wedge on selected endpoint
+ * cdns3_gadget_ep_set_wedge - Set wedge on selected endpoint
  * @ep: endpoint object
  *
  * Returns 0
···
 }
 
 /**
- * cdns3_init_ep0 Initializes software endpoint 0 of gadget
+ * cdns3_init_ep0 - Initializes software endpoint 0 of gadget
  * @priv_dev: extended gadget object
  * @priv_ep: extended endpoint object
  *