iio: adc: mcp3911: add support for the whole MCP39xx family

Microchip does have many similar chips, add support for those.

The new supported chips are:
  - microchip,mcp3910
  - microchip,mcp3912
  - microchip,mcp3913
  - microchip,mcp3914
  - microchip,mcp3918
  - microchip,mcp3919
Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230822192259.1125792-7-marcus.folkesson@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/Kconfig

@@ -785,8 +785,10 @@ config MCP3911
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
 	help
-	  Say yes here to build support for Microchip Technology's MCP3911
-	  analog to digital converter.
+	  Say yes here to build support for one of the following
+	  Microchip Technology's analog to digital converters:
+	  MCP3910, MCP3911, MCP3912, MCP3913, MCP3914,
+	  MCP3918 and MCP3919.
 
 	  This driver can also be built as a module. If so, the module will be
 	  called mcp3911.