CVE-2026-80887 drm/vmwgfx: use check_add_overflow for shader size+offset bound

In the Linux kernel, the following vulnerability has been resolved: drm/vmwgfx: use checkaddoverflow for shader size+offset bound vmwshaderdefine validates the user-supplied shader window against its backing buffer with u64buffer-tbo.base.size guestmemoryoffset and forwarded to host SVGA...