dt-bindings: pinctrl: sunxi: Fix reference to driver

Bindings describe hardware, not drivers.
Use reference to hardware Allwinner A1X Pin Controller instead driver.

Signed-off-by: Matheus Castello <[e-mail]>
Signed-off-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt

···
 configuration, drive strength and pullups. If one of these options is
 not set, its actual value will be unspecified.
 
-This driver supports the generic pin multiplexing and configuration
-bindings. For details on each properties, you can refer to
-./pinctrl-bindings.txt.
+Allwinner A1X Pin Controller supports the generic pin multiplexing and
+configuration bindings. For details on each properties, you can refer to
+ ./pinctrl-bindings.txt.
 
 Required sub-node properties:
   - pins