docs: driver-model: move it to the driver-api book

The audience for the Kernel driver-model is clearly Kernel hackers.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> # ice driver changes

Documentation/driver-api/gpio/driver.rst

@@ -399,7 +399,7 @@ symbol:
   will pass the struct gpio_chip* for the chip to all IRQ callbacks, so the
   callbacks need to embed the gpio_chip in its state container and obtain a
   pointer to the container using container_of().
-  (See Documentation/driver-model/design-patterns.rst)
+  (See Documentation/driver-api/driver-model/design-patterns.rst)
 
 - gpiochip_irqchip_add_nested(): adds a nested cascaded irqchip to a gpiochip,
   as discussed above regarding different types of cascaded irqchips. The