iio: frequency: Kconfig: AD9172 select REGMAP_SPI

The driver uses regmap spi modpost symbols such as devm_regmap_init_spi.

Signed-off-by: Jorge Marques <[email protected]>

Author: gastmaier

drivers/iio/frequency/Kconfig

@@ -139,6 +139,7 @@ config CF_AXI_DDS_AD9162
 config CF_AXI_DDS_AD9172
 	tristate "Analog Devices AD917x DAC"
 	depends on CF_AXI_DDS
+	select REGMAP_SPI
 	help
 	  Say yes here to build support for Analog Devices AD917x DAC chip
 	  ad917x, provides direct access via sysfs.