ivi-layout: remove ivi_layout_surface_set_native_content.

There are two use case to
- create ivi_surface without wl_surface to set property in advanced
- keep property per ID during deletion of ivi_surface.

This is supported later. For the time being, remove this function.

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
ivi-shell: ivi-shell.c, remove surface_set_native_content.

There are two use case to
- create ivi_surface without wl_surface to set property in advanced
- keep property per ID during deletion of ivi_surface.

This is supported later. For the time being, remove this function.

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>