usb: gadget: udc: renesas_usb3: Fix compiler warning

usb: gadget: udc: renesas_usb3: Fix compiler warning

drivers/usb/gadget/udc/renesas_usb3.c: In function 'renesas_usb3_probe':
drivers/usb/gadget/udc/renesas_usb3.c:2638:73: warning: '%d'
directive output may be truncated writing between 1 and 11 bytes into a
region of size 6 [-Wformat-truncation=]
2638 |   snprintf(usb3_ep->ep_name, sizeof(usb3_ep->ep_name), "ep%d", i);
                                    ^~~~~~~~~~~~~~~~~~~~~~~~     ^~   ^

Fixes: 746bfe63bba3 ("usb: gadget: renesas_usb3: add support for Renesas USB3.0 peripheral controller")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501201409.BIQPtkeB-lkp@intel.com/
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Link: https://lore.kernel.org/r/20250122081231.47594-1-guoren@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>