rockchip: rk3328-orangepi-r1-plus: Enable boot from SPI NOR flash

Add Kconfig options to enable support for booting from SPI NOR flash on
Orange Pi R1 Plus boards.

The generated bootable u-boot-rockchip-spi.bin can be written to 0x0 of
SPI NOR flash. The FIT image is loaded from 0x60000, same as on RK35xx
boards.

  => sf probe
  SF: Detected zb25vq128 with page size 256 Bytes, erase size 4 KiB, total 16 MiB

  => load mmc 1:1 10000000 u-boot-rockchip-spi.bin
  1376768 bytes read in 66 ms (19.9 MiB/s)

  => sf update ${fileaddr} 0 ${filesize}
  device 0 offset 0x0, size 0x150200
  1126912 bytes written, 249856 bytes skipped in 14.22s, speed 100542 B/s

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Tianling Shen <cnsztl@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>