gpu: host1x: Correct swapped arguments in the is_addr_reg() definition

Arguments of the .is_addr_reg() are swapped in the definition of the
function, that is quite confusing.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Erik Faye-Lund <kusmabite@gmail.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>