usb: gadget: composite: Use USB API functions rather than constants

Use the function usb_endpoint_num() rather than constants.

The Coccinelle semantic patch is as follows:

@@ struct usb_endpoint_descriptor *epd; @@

- (epd->bEndpointAddress & \(USB_ENDPOINT_NUMBER_MASK\|0x0f\))
+ usb_endpoint_num(epd)

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://lore.kernel.org/r/20250618035540.290411-1-nichen@iscas.ac.cn


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>