iio: adc: adi-axi-adc: add platform dependencies

Being this device a soft core, it's only supported on some/specific
platforms. Hence add proper dependencies for the supported platforms.
Also add COMPILE_TEST to increase the build coverage.
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240604-dev-axi-adc-kconfig-v1-1-cfb725606b8e@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/Kconfig

@@ -353,6 +353,7 @@ config AD9467
 
 config ADI_AXI_ADC
 	tristate "Analog Devices Generic AXI ADC IP core driver"
+	depends on MICROBLAZE || NIOS2 || ARCH_ZYNQ || ARCH_ZYNQMP || ARCH_INTEL_SOCFPGA || COMPILE_TEST
 	select IIO_BUFFER
 	select IIO_BUFFER_HW_CONSUMER
 	select IIO_BUFFER_DMAENGINE