Move the pcf8591 driver to hwmon

Directory drivers/i2c/chips is going away, so drivers there must find
new homes. For the pcf8591 driver, the best choice seems to be the
hwmon subsystem. While the Philips PCF8591 device isn't a typical
hardware monitoring chip, its DAC interface is compatible with the
hwmon one, so it fits somewhat.

If a better subsystem is ever created for ADC/DAC chips, the driver
could be moved there.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 0eb4170..9a22816 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -635,6 +635,20 @@
 	  This driver can also be built as a module.  If so, the module
 	  will be called pc87427.
 
+config SENSORS_PCF8591
+	tristate "Philips PCF8591 ADC/DAC"
+	depends on I2C
+	default n
+	help
+	  If you say yes here you get support for Philips PCF8591 4-channel
+	  ADC, 1-channel DAC chips.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called pcf8591.
+
+	  These devices are hard to detect and rarely found on mainstream
+	  hardware.  If unsure, say N.
+
 config SENSORS_SIS5595
 	tristate "Silicon Integrated Systems Corp. SiS5595"
 	depends on PCI