dt-bindings:iio:adc:remove atmel, adc-res and atmel, adc-res-names

Remove atmel,adc-res and atmel,adc-res-names as they are not necessary and
are handled by the driver. Also add sama5d3 to the list of possible chips.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Rob Herring <robh+dt@kernel.org>
Link: https://lore.kernel.org/r/20201128222818.1910764-4-alexandre.belloni@bootlin.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/at91_adc.txt

@@ -2,7 +2,7 @@
 
 Required properties:
   - compatible: Should be "atmel,<chip>-adc"
-    <chip> can be "at91sam9260", "at91sam9g45" or "at91sam9x5"
+    <chip> can be "at91sam9260", "at91sam9g45", "at91sam9x5" or "sama5d3"
   - reg: Should contain ADC registers location and length
   - interrupts: Should contain the IRQ line for the ADC
   - clock-names: tuple listing input clock names.
@@ -13,17 +13,12 @@ Required properties:
   - atmel,adc-startup-time: Startup Time of the ADC in microseconds as
     defined in the datasheet
   - atmel,adc-vref: Reference voltage in millivolts for the conversions
-  - atmel,adc-res: List of resolutions in bits supported by the ADC. List size
-		   must be two at least.
-  - atmel,adc-res-names: Contains one identifier string for each resolution
-			 in atmel,adc-res property. "lowres" and "highres"
-			 identifiers are required.
 
 Optional properties:
   - atmel,adc-use-external-triggers: Boolean to enable the external triggers
-  - atmel,adc-use-res: String corresponding to an identifier from
-		       atmel,adc-res-names property. If not specified, the highest
-		       resolution will be used.
+  - atmel,adc-use-res: String selecting the resolution, can be "lowres" or
+		       "highres". If not specified, the highest resolution will
+		       be used.
   - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
   - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
   - atmel,adc-ts-wires: Number of touchscreen wires. Should be 4 or 5. If this