eglvivsink: added mutex locks for element properties

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
eglvivsink: added native-display property

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>
eglvivsink: added force-aspect-ratio property

Signed-off-by: Carlos Rafael Giani <dv@pseudoterminal.org>