CVE-2026-63882 drm/amdkfd: fix NULL pointer bug in svm_range_set_attr

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: fix NULL pointer bug in svmrangesetattr The processinfo could be NULL if user doesn't call kfdioctlacquirevm before calling kfdioctlsvm. cherry picked from commit 83a26c812e0529eb040d31a76f73e33e637243d4...