gpio: wcove: Use -ENOTSUPP consistently

The GPIO library expects the drivers to return -ENOTSUPP in some
cases and not using analogue POSIX code. Make the driver to follow
this.

Reviewed-by: Kuppuswamy Sathyanarayanan <[e-mail]>
Signed-off-by: Andy Shevchenko <[e-mail]>

drivers/gpio/gpio-wcove.c

···
 	unsigned int reg = type == CTRL_IN ? GPIO_IN_CTRL_BASE : GPIO_OUT_CTRL_BASE;
 
 	if (gpio >= WCOVE_GPIO_NUM)
-		return -EOPNOTSUPP;
+		return -ENOTSUPP;
 
 	return reg + gpio;
 }