[FS#476] fail to detect usb storage at boot time on apu2c4.

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - KazukiShimada (KazukiShimada) 

Attached to Project - LEDE Project
Summary - fail to detect usb storage at boot time on apu2c4.
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - High
Priority - Very Low
Reported Version - All
Due in Version - Undecided
Due Date - Undecided
Details - version: 17.01.0-rc1, r3042-ec095b5 and latest master
device: pcengine apu2c4, toshiba 32GB usb3.0 storage
packages: kmod-usb-storage, kmod-usb-core, kmod-scsi-core


After boot, inserting usb storage is detected successfully, like this
=======================================================================================
BusyBox v1.25.1 () built-in shell (ash)

     _________
    /        /\      _    ___ ___  ___
   /  LE    /  \    | |  | __|   \| __|
  /    DE  /    \   | |__| _|| |) | _|
 /________/  LE  \  |____|___|___/|___|                      lede-project.org
 \        \   DE /
  \    LE  \    /  -----------------------------------------------------------
   \  DE    \  /    Reboot (17.01.0-rc1, r3042-ec095b5)
    \________\/    -----------------------------------------------------------

root at lede:/# ls /dev/|grep sd            (