drivers: adc: mcp320x: fix compilation when using spi cs-gpios
drivers: adc: mcp320x: fix compilation when using spi cs-gpios

Fix compilation of the MCP320x ADC driver when using SPI cs-gpios.

Fixes 0f7acb1dc362343d8033373e1de7ff9737b5af7c.

Signed-off-by: Henrik Brix Andersen <24a3f13c22635bab658e39fc5f1e63c575328aae@vestas.com>

Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,finikorg/zephyr,Vudentz/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr