The spi which's version is higher than ver 2 will automatically
enable this feature.

If the length of master transmission is uncertain, the RK spi slave
is better to automatically stop after cs inactive instead of waiting
for xfer_completion forever.
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Link: https://lore.kernel.org/r/20220216014028.8123-4-jon.lin@rock-chips.comSigned-off-by: Mark Brown <broonie@kernel.org>