usbplug: rk3562: Support SPI Flash

Change-Id: Ife2654531fe5fe0991e4673542a52da6eb5eced1
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>

usbplug: add usbplug support for rk3562

Signed-off-by: Yifeng Zhao <yifeng.zhao@rock-chips.com>
Change-Id: If092583b0093cfe9c8cc27636307a2dc143d1b1a