Merge pull request #549 from stevstrong/patch-17

F4: USBD_StrDesc[] size fix

Author: rogerclarkmelbourne

STM32F4/cores/maple/libmaple/usbF4/VCP/usbd_conf.h

@@ -32,7 +32,7 @@
   */
 #define USBD_CFG_MAX_NUM                1
 #define USBD_ITF_MAX_NUM                1
-#define USB_MAX_STR_DESC_SIZ            50
+#define USB_MAX_STR_DESC_SIZ            (64+4) // longest descriptor string length + 2
 
 /** @defgroup USB_VCP_Class_Layer_Parameter
   * @{