In U-Boot -ENODEV means that there is no device. When there is a problem
with the device, drivers should return an error like -ENXIO or -EREMOTEIO.
When the device tree properties cannot be read correct , they should
return -EINVAL.

Update various GPIO drivers to follow this rule, to help with consistency
for future driver writers.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Adam Ford <aford173@gmail.com>