Correct the kerneldoc for structure to fix W=1 compile warning:

    drivers/spi/spi-s3c24xx.c:36: warning: cannot understand function prototype: 'struct s3c24xx_spi_devstate '
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Andi Shyti <andi@etezian.org>
Link: https://lore.kernel.org/r/20200804151356.28057-1-krzk@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>