AP_Bootloader: for fast boot don't init USB

Tools/AP_Bootloader/AP_Bootloader.cpp

@@ -42,8 +42,6 @@ struct boardinfo board_info;
 
 int main(void)
 {
-    init_uarts();
-
     board_info.board_type = APJ_BOARD_ID;
     board_info.board_rev = 0;
     board_info.fw_size = (BOARD_FLASH_SIZE - FLASH_BOOTLOADER_LOAD_KB)*1024;
@@ -51,8 +49,6 @@ int main(void)
         board_info.fw_size = (1024 - FLASH_BOOTLOADER_LOAD_KB)*1024;        
     }
 
-    flash_init();
-
     bool try_boot = false;
     uint32_t timeout = HAL_BOOTLOADER_TIMEOUT;
 
@@ -72,6 +68,9 @@ int main(void)
         jump_to_app();
     }
 
+    init_uarts();
+    flash_init();
+    
     while (true) {
         bootloader(timeout);
         jump_to_app();