iio: cdc: ad7746: Move driver out of staging.

All known major issues with this driver resolved so time to move
it out of staging. This also allows us to remove the now empty
staging/iio/cdc directory and build files.

Note this cleanup work was done using the roadtest framework.
https://lore.kernel.org/all/20220311162445.346685-1-vincent.whitchurch@axis.com/Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

drivers/iio/cdc/Kconfig

@@ -14,4 +14,14 @@ config AD7150
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad7150.
 
+config AD7746
+	tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Analog Devices capacitive sensors.
+	  (AD7745, AD7746, AD7747) Provides direct access via sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad7746.
+
 endmenu

drivers/iio/cdc/Makefile

@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_AD7150) += ad7150.o
+obj-$(CONFIG_AD7746) += ad7746.o

drivers/staging/iio/Kconfig

@@ -8,7 +8,6 @@ menu "IIO staging drivers"
 source "drivers/staging/iio/accel/Kconfig"
 source "drivers/staging/iio/adc/Kconfig"
 source "drivers/staging/iio/addac/Kconfig"
-source "drivers/staging/iio/cdc/Kconfig"
 source "drivers/staging/iio/frequency/Kconfig"
 source "drivers/staging/iio/impedance-analyzer/Kconfig"
 source "drivers/staging/iio/meter/Kconfig"

drivers/staging/iio/Makefile

@@ -6,7 +6,6 @@
 obj-y += accel/
 obj-y += adc/
 obj-y += addac/
-obj-y += cdc/
 obj-y += frequency/
 obj-y += impedance-analyzer/
 obj-y += meter/

drivers/staging/iio/cdc/Kconfig

-# SPDX-License-Identifier: GPL-2.0
-#
-# CDC drivers
-#
-menu "Capacitance to digital converters"
-
-config AD7746
-	tristate "Analog Devices AD7745, AD7746 AD7747 capacitive sensor driver"
-	depends on I2C
-	help
-	  Say yes here to build support for Analog Devices capacitive sensors.
-	  (AD7745, AD7746, AD7747) Provides direct access via sysfs.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called ad7746.
-
-endmenu

drivers/staging/iio/cdc/Makefile

-# SPDX-License-Identifier: GPL-2.0
-#
-# Makefile for industrial I/O CDC drivers
-#
-
-obj-$(CONFIG_AD7746) += ad7746.o