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 <hebad@vestas.com>
1 file changed