ivi-shell: add input panel label func

Copied from desktop-shell/input-panel.c, add a label function for the
input panel.

This patch strictly reduces the difference between input-panel.c and
input-panel-ivi.c.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Eugen Friedrich <friedrix@gmail.com>
1 file changed