soc/tegra: pmc: Don't fail if "aotag" is not present

soc/tegra: pmc: Don't fail if "aotag" is not present

The "aotog" is an optional aperture, so if that aperture is not defined
for a given device, then initialise the 'aotag' pointer to NULL instead
of returning an error. Note that the PMC driver will not use 'aotag'
pointer if initialised to NULL.

Co-developed-by: Shardar Mohammed <smohammed@nvidia.com>
Signed-off-by: Shardar Mohammed <smohammed@nvidia.com>
Signed-off-by: Prathamesh Shete <pshete@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>