Fix IAR warnings.

Pa039 : use of address of unaligned structure member.
Pe188: enumerated type mixed with another type.

src/class/hid/hid_device.c

@@ -194,7 +194,9 @@ uint16_t hidd_open(uint8_t rhport, tusb_desc_interface_t const * desc_itf, uint1
 
   p_hid->boot_mode = false; // default mode is REPORT
   p_hid->itf_num   = desc_itf->bInterfaceNumber;
-  memcpy(&p_hid->report_desc_len, &(p_hid->hid_descriptor->wReportLength), 2);
+  
+  // Use offsetof to avoid pointer to the odd/misaligned address
+  memcpy(&p_hid->report_desc_len, (uint8_t*) p_hid->hid_descriptor + offsetof(tusb_hid_descriptor_hid_t, wReportLength), 2);
 
   // Prepare for output endpoint
   if (p_hid->ep_out)