spi: spi-rockchip: Fix out of bounds array access

spi: spi-rockchip: Fix out of bounds array access

Since spi-rockchip enables use_gpio_descriptors and the
SPI_CONTROLLER_GPIO_SS flag, the spi subsytem may call set_cs()
for spi devices with indexes above ROCKCHIP_SPI_MAX_CS_NUM

Remove array cs_asserted[] which held a shadow copy of the state
of the chip select lines with the only purpose of optimizing out
rewriting a chip select line to the current state (no-op)
This case is already handled by spi.c

Signed-off-by: Luis de Arquer <luis.dearquer@inertim.com>
Link: https://lore.kernel.org/r/d0a0c4b94f933f7f43973c34765214303ee82b77.camel@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>