Fixed MIDI descriptors

To be compliant with the one sent by the AVR core

cores/arduino/USB/USBCore.h

@@ -251,13 +251,13 @@ typedef struct
 _Pragma("pack()")
 
 #define D_DEVICE(_class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs) \
-	{ 18, 1, 0x110, _class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs }
+	{ 18, 1, 0x200, _class,_subClass,_proto,_packetSize0,_vid,_pid,_version,_im,_ip,_is,_configs }
 /* Table 9-8. Standard Device Descriptor
  * bLength, bDescriptorType, bcdUSB, bDeviceClass, bDeviceSubClass, bDeviceProtocol, bMaxPacketSize0,
  *    idVendor, idProduct, bcdDevice, iManufacturer, iProduct, iSerialNumber, bNumConfigurations */
 
 #define D_CONFIG(_totalLength,_interfaces) \
-	{ 9, 2, _totalLength,_interfaces, 1, 0, USB_CONFIG_SELF_POWERED, USB_CONFIG_POWER_MA(500) }
+	{ 9, 2, _totalLength,_interfaces, 1, 0, USB_CONFIG_BUS_POWERED, USB_CONFIG_POWER_MA(500) }
 /* Table 9-10. Standard Configuration Descriptor
  * bLength, bDescriptorType, wTotalLength, bNumInterfaces, bConfigurationValue, iConfiguration
  * bmAttributes, bMaxPower */
@@ -275,7 +275,7 @@ _Pragma("pack()")
 
 #define D_IAD(_firstInterface, _count, _class, _subClass, _protocol) \
 	{ 8, 11, _firstInterface, _count, _class, _subClass, _protocol, 0 }
-/* iadclasscode_r10.pdf, Table 9Z. Standard Interface Association Descriptor
+/* iadclasscode_r10.pdf, Table 9\96Z. Standard Interface Association Descriptor
  * bLength, bDescriptorType, bFirstInterface, bInterfaceCount, bFunctionClass, bFunctionSubClass, bFunctionProtocol, iFunction */
 
 // Functional Descriptor General Format