dm: adc: add iMX93 ADC support

This commit adds driver for iMX93 ADC.

The driver is implemented using driver model and provides
ADC uclass's methods for ADC single channel operations:
    - adc_start_channel()
    - adc_channel_data()
    - adc_stop()

ADC features:
    - channels: 4
    - resolution: 12-bit

Signed-off-by: Luca Ellero <l.ellero@asem.it>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
diff --git a/drivers/adc/Kconfig b/drivers/adc/Kconfig
index e719c38..4336732 100644
--- a/drivers/adc/Kconfig
+++ b/drivers/adc/Kconfig
@@ -63,3 +63,11 @@
 	  - core driver to deal with common resources
 	  - child driver to deal with individual ADC resources (declare ADC
 	  device and associated channels, start/stop conversions)
+
+config ADC_IMX93
+	bool "Enable NXP IMX93 ADC driver"
+	help
+	  This enables basic driver for NXP IMX93 ADC.
+	  It provides:
+	  - 4 analog input channels
+	  - 12-bit resolution