The Radxa Rock Pi 4 board is sold from revision 1.4 with a soldered 4Mb SPI NOR Flash. This series allows to use it from U-Boot and boot from it.

This series applies to u-boot/next.

Changes since v1:

- Changed bus number to 1 in SPL to match U-Boot proper (before it was bus 0 in SPL and bus 1 in U-Boot).

- Generalization. v1 did a first soft_reset in 8_8_8_DTR but that wouldn't work since Pratyush Yadav fixed supports_op() in commit 5752d6ae8daacbd ("spi: spi-mem: add spi_mem_dtr_supports_op()"). So now we try a few protocols until 1_1_1 is supported by controller and device. Might work for more systems.