dma: atmel-dma: correct typo in the device tree bindings documentation

The value to set ASAP mode for FIFO configuration is 2 instead of 1.
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

Documentation/devicetree/bindings/dma/atmel-dma.txt

@@ -28,7 +28,7 @@ The three cells in order are:
 dependent:
   - bit 7-0: peripheral identifier for the hardware handshaking interface. The
   identifier can be different for tx and rx.
-  - bit 11-8: FIFO configuration. 0 for half FIFO, 1 for ALAP, 1 for ASAP.
+  - bit 11-8: FIFO configuration. 0 for half FIFO, 1 for ALAP, 2 for ASAP.
 
 Example: