HID: merged HID_Descriptor into HIDDescriptorListNode

This simplifies the object model and produce a small gain in code
size and performance.

Author: cmaglie

libraries/HID/HID.cpp

@@ -68,7 +68,7 @@ int HID_GetDescriptor(int8_t t)
 		HIDDescriptorListNode* current = rootNode;
 		int total = 0;
 		while(current != NULL) {
-			total += USBD_SendControl(0,current->descriptor->data,current->descriptor->length);
+			total += USBD_SendControl(0,current->data,current->length);
 			current = current->next;
 		}
 		return total;
@@ -89,7 +89,7 @@ void HID_::AppendDescriptor(HIDDescriptorListNode *node)
 		current->next = node;
 	}
 	modules_count++;
-	sizeof_hidReportDescriptor += node->descriptor->length;
+	sizeof_hidReportDescriptor += node->length;
 }
 
 void HID_::SendReport(uint8_t id, const void* data, int len)

libraries/HID/HID.h

@@ -42,16 +42,12 @@
 #define HID_REPORT_DESCRIPTOR_TYPE      0x22
 #define HID_PHYSICAL_DESCRIPTOR_TYPE    0x23
 
-typedef struct __attribute__((packed)) {
-  uint8_t length;
-  const void* data;
-} HID_Descriptor;
-
 class HIDDescriptorListNode {
 public:
   HIDDescriptorListNode *next = NULL;
-  const HID_Descriptor *descriptor;
-  HIDDescriptorListNode(const HID_Descriptor *d) : descriptor(d) { }
+  HIDDescriptorListNode(const void *d, uint16_t l) : data(d), length(l) { }
+  uint8_t length;
+  const void* data;
 };
 
 class HID_