spi/rockchip: Add dependencies on relaxed I/O accessors

Without the dependencies for the accessors the driver can be enabled on
architectures where it will fail to build.

Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index f414313..79ace88 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -384,6 +384,7 @@
 
 config SPI_ROCKCHIP
 	tristate "Rockchip SPI controller driver"
+	depends on ARM || ARM64 || AVR32 || HEXAGON || MIPS || SUPERH
 	help
 	  This selects a driver for Rockchip SPI controller.