usb: gadget: udc: remove unused usbf_ep_dma_reg_clrset function

clang with W=1 reports
drivers/usb/gadget/udc/renesas_usbf.c:548:20: error: unused function
  'usbf_ep_dma_reg_clrset' [-Werror,-Wunused-function]
static inline void usbf_ep_dma_reg_clrset(struct usbf_ep *ep, uint offset,
                   ^
This function is not used, so remove it.
Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Herve Codina <herve.codina@bootlin.com>
Link: https://lore.kernel.org/r/20230319155910.1706294-1-trix@redhat.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/renesas_usbf.c

@@ -545,17 +545,6 @@ static inline void usbf_ep_dma_reg_bitclr(struct usbf_ep *ep, uint offset,
 	usbf_ep_dma_reg_writel(ep, offset, tmp);
 }
 
-static inline void usbf_ep_dma_reg_clrset(struct usbf_ep *ep, uint offset,
-					  u32 clr, u32 set)
-{
-	u32 tmp;
-
-	tmp = usbf_ep_dma_reg_readl(ep, offset);
-	tmp &= ~clr;
-	tmp |= set;
-	usbf_ep_dma_reg_writel(ep, offset, tmp);
-}
-
 static void usbf_ep0_send_null(struct usbf_ep *ep0, bool is_data1)
 {
 	u32 set;