configs:rockchip:roc-rk3399-pc:Enable more configs

This patch enables the following:

1) use preboot configuration to enable usb devices.

2) Enable USB configs so keyboards and other USB devices work,
   update the number of ports of the usb root hub.

   - with this addition the updated USB device Tree:

	1  Hub (12 Mb/s, 0mA)
	U-Boot Root Hub
	1  Hub (12 Mb/s, 0mA)
	|   U-Boot Root Hub
	|
	+-2  Hub (12 Mb/s, 100mA)
	USB 2.0 Hub [MTT]

	1  Hub (5 Gb/s, 0mA)
	U-Boot XHCI Host Controller

3) enable crypto RNG support.

4) Change SPI speed and frequency:
    - increase the maximum SPI slave device speed,
      SPI flash max frequency for the environment from 10Mhz to 30MHz.

    - performance stats for speed update from 10MHz to 30MHz:

    	with 10Mhz speed update:
    	 => sf update 0x300000 0x800000 0x400000
    	    4194304 bytes written, 0 bytes skipped in 36.819s, speed 119837 B/s

        with 30Mhz speed update:
    	 => sf update 0x300000 0x800000 0x400000
    	    4194304 bytes written, 0 bytes skipped in 20.319s, speed 220752 B/s

Signed-off-by: Manoj Sai <abbaraju.manojsai@amarulasolutions.com>
Signed-off-by: Da Xue <da.xue@libretech.co>
Signed-off-by: dsx724 <da@lessconfused.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>