gpu: host1x: Drop unnecessary host1x argument

Functions taking a pointer to a host1x syncpoint as an argument don't
need to specify a pointer to a host1x instance because it can be
obtained from the syncpoint.

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