ui/sdl2: clear guest_fb.dmabuf on release

sdl2_gl_release_dmabuf() releases the texture but leaves the
guest_fb.dmabuf pointer dangling. Clear it to prevent stale
references after the dmabuf is freed.

Fixes: 52053b7e0a0e ("ui/sdl2: Implement dpy dmabuf functions")
Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
1 file changed