spi-rockchip: Fix register out of bounds access

[ Upstream commit 7a874e8b ]

Do not write native chip select stuff for GPIO chip selects.
GPIOs can be numbered much higher than native CS.
Also, it makes no sense.

Signed-off-by: Luis de Arquer <luis.dearquer@inertim.com>
Link: https://patch.msgid.link/365ccddfba110549202b3520f4401a6a936e82a8.camel@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>