gpu: nvgpu: protect against integer overflow

(cherry pick from commit af023fc9aab16521a9a86fd6586f6334c90cf26a)

Check offset value of nvgpu notifiers to protect against
potential unsigned integer overflow.

Signed-off-by: Xia Yang <xiay@nvidia.com>
Bug: 27299111
Bug: 27297988
Change-Id: I59bff9c0d5191472464834c6064a5e57ce9d554f
1 file changed