sandbox: gpio: doc: Fix parameter documentation

The documentation of parameters in arch/sandbox/include/asm/gpio.h is
either missing or faulty.

This patch corrects the documentation.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Acked-by: Simon Glass <sjg@chromium.org>

arch/sandbox/include/asm/gpio.h

@@ -26,7 +26,8 @@
 /**
  * Return the simulated value of a GPIO (used only in sandbox test code)
  *
- * @param gp	GPIO number
+ * @param dev		device to use
+ * @param offset	GPIO offset within bank
  * @return -1 on error, 0 if GPIO is low, >0 if high
  */
 int sandbox_gpio_get_value(struct udevice *dev, unsigned int offset);
@@ -34,8 +35,9 @@ int sandbox_gpio_get_value(struct udevice *dev, unsigned int offset);
 /**
  * Set the simulated value of a GPIO (used only in sandbox test code)
  *
- * @param gp	GPIO number
- * @param value	value to set (0 for low, non-zero for high)
+ * @param dev		device to use
+ * @param offset	GPIO offset within bank
+ * @param value		value to set (0 for low, non-zero for high)
  * @return -1 on error, 0 if ok
  */
 int sandbox_gpio_set_value(struct udevice *dev, unsigned int offset, int value);
@@ -63,7 +65,8 @@ int sandbox_gpio_get_open_drain(struct udevice *dev, unsigned offset);
 /**
  * Return the simulated direction of a GPIO (used only in sandbox test code)
  *
- * @param gp	GPIO number
+ * @param dev		device to use
+ * @param offset	GPIO offset within bank
  * @return -1 on error, 0 if GPIO is input, >0 if output
  */
 int sandbox_gpio_get_direction(struct udevice *dev, unsigned int offset);
@@ -71,8 +74,9 @@ int sandbox_gpio_get_direction(struct udevice *dev, unsigned int offset);
 /**
  * Set the simulated direction of a GPIO (used only in sandbox test code)
  *
- * @param gp	GPIO number
- * @param output 0 to set as input, 1 to set as output
+ * @param dev		device to use
+ * @param offset	GPIO offset within bank
+ * @param output 	0 to set as input, 1 to set as output
  * @return -1 on error, 0 if ok
  */
 int sandbox_gpio_set_direction(struct udevice *dev, unsigned int offset,