gpu: host1x: Use not explicitly sized types

The number of words and the offset in a gather don't need to be
explicitly sized, so make them unsigned int instead.

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>