MAINTAINERS: improve section MICROCHIP MCP3564 ADC DRIVER

Commit 33ec3e5f ("iio: adc: adding support for MCP3564 ADC") adds a new
iio driver and corresponding MAINTAINERS section. It however uses spaces
instead of a single tab for all the entries in that MAINTAINERS section.

Although, the get_maintainer.pl script handles spaces instead of tabs
silently, the MAINTAINERS will quickly get into a messy state with
different indentations throughout the file. So, the checkpatch.pl script
complains when spaces instead of a single tab are used.

Fix this recently added section using tabs instead of spaces.
Further, add the driver's ABI documentation file to this section as well.

Fixes: 33ec3e5f ("iio: adc: adding support for MCP3564 ADC")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20231122075629.21411-1-lukas.bulwahn@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -14196,11 +14196,12 @@ F:	Documentation/devicetree/bindings/regulator/mcp16502-regulator.txt
 F:	drivers/regulator/mcp16502.c
 
 MICROCHIP MCP3564 ADC DRIVER
-M:      Marius Cristea <marius.cristea@microchip.com>
-L:      linux-iio@vger.kernel.org
-S:      Supported
-F:      Documentation/devicetree/bindings/iio/adc/microchip,mcp3564.yaml
-F:      drivers/iio/adc/mcp3564.c
+M:	Marius Cristea <marius.cristea@microchip.com>
+L:	linux-iio@vger.kernel.org
+S:	Supported
+F:	Documentation/ABI/testing/sysfs-bus-iio-adc-mcp3564
+F:	Documentation/devicetree/bindings/iio/adc/microchip,mcp3564.yaml
+F:	drivers/iio/adc/mcp3564.c
 
 MICROCHIP MCP3911 ADC DRIVER
 M:	Marcus Folkesson <marcus.folkesson@gmail.com>