drivers: gpio: Fix trivial spelling

The word 'descriptor' is misspelled throughout the tree.

Fix it up accordingly:
    decriptors -> descriptors

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/TODO

@@ -5,7 +5,7 @@ subsystem.
 GPIO descriptors
 
 Starting with commit 79a9becda894 the GPIO subsystem embarked on a journey
-to move away from the global GPIO numberspace and toward a decriptor-based
+to move away from the global GPIO numberspace and toward a descriptor-based
 approach. This means that GPIO consumers, drivers and machine descriptions
 ideally have no use or idea of the global GPIO numberspace that has/was
 used in the inception of the GPIO subsystem.