kernel: drm/vmwgfx: fix integer overflow in vmw_surface_define_ioctl()

An out-of-bounds write vulnerability was found in the Linux kernel's vmwsurfacedefineioctl function, in the 'drivers/gpu/drm/vmwgfx/vmwgfxsurface.c' file. Due to the nature of the flaw, privilege escalation cannot be fully ruled out, although we believe it is unlikely...