usb: gadget: udc: udc-xilinx: Add identifier to read_fn function arg

Add an identifier in the read_fn function declaration because based on
commit ca0d8929 ("checkpatch: add warning for unnamed function
definition arguments") it is the preferred coding style even C standard
allows both formats.
Signed-off-by: Piyush Mehta <piyush.mehta@amd.com>
Message-ID: <20230607072959.2334046-1-piyush.mehta@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/udc-xilinx.c

@@ -192,7 +192,7 @@ struct xusb_udc {
 	bool dma_enabled;
 	struct clk *clk;
 
-	unsigned int (*read_fn)(void __iomem *);
+	unsigned int (*read_fn)(void __iomem *reg);
 	void (*write_fn)(void __iomem *, u32, u32);
 };