usb: gadget: udc: pxa27x_udc: Fix documentation for 'pxa27x_udc_start()'

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

 drivers/usb/gadget/udc/pxa27x_udc.c:1749: warning: expecting prototype for pxa27x_start(). Prototype was for pxa27x_udc_start() instead

Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-usb@vger.kernel.org
Acked-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210526130037.856068-19-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/pxa27x_udc.c

@@ -1728,7 +1728,7 @@ static void udc_enable(struct pxa_udc *udc)
 }
 
 /**
- * pxa27x_start - Register gadget driver
+ * pxa27x_udc_start - Register gadget driver
  * @g: gadget
  * @driver: gadget driver
  *