spi: sun6i: add quirk for in-controller clock divider

Previously SPI controllers in Allwinner SoCs has a clock divider inside.
However now the clock divider is removed and to set the transfer clock
rate it's only needed to set the SPI module clock to the target value
and configure a proper work mode.

According to the datasheet there are three work modes:

| SPI Sample Mode         | SDM(bit13) | SDC(bit11) | Run Clock |
|-------------------------|------------|------------|-----------|
| normal sample           |      1     |      0     | <= 24 MHz |
| delay half cycle sample |      0     |      0     | <= 40 MHz |
| delay one cycle sample  |      0     |      1     | >= 80 MHz |

Add a quirk for this kind of SPI controllers.

Co-developed-by: Icenowy Zheng <icenowy@aosc.io
Signed-off-by: Maksim Kiselev <bigunclemax@gmail.com
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com
Reviewed-by: Andre Przywara <andre.przywara@arm.com
Link: https://lore.kernel.org/r/20230510081121.3463710-4-bigunclemax@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org

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