dt-bindings: ata: ahci-platform: fix indentation of target-supply

This patch fix the indentation of target-supply's ':'.
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/devicetree/bindings/ata/ahci-platform.txt

@@ -47,7 +47,7 @@ Sub-nodes required properties:
 - reg		    : the port number
 And at least one of the following properties:
 - phys		    : reference to the SATA PHY node
-- target-supply    : regulator for SATA target power
+- target-supply     : regulator for SATA target power
 
 Examples:
         sata@ffe08000 {