CVE-2026-63863 drm/gpusvm: Fix unbalanced unlock in drm_gpusvm_scan_mm()

In the Linux kernel, the following vulnerability has been resolved: drm/gpusvm: Fix unbalanced unlock in drmgpusvmscanmm There is a unbalanced lock/unlock to gpusvm notifier lock: 931.045868 ===================================== 931.046509 WARNING: bad unlock balance detected! 931.047149...