Add documentation links to example swupdate.service
Add documentation links to example swupdate.service

Signed-off-by: Christian Storm <9b0ad956043d7985515d8cbb7db6d934a5db2634@siemens.com>
Reviewed-by: Stefano Babic <2c2905e0c2877c7e4ce40c7425e972302953fda5@denx.de>

sbabic/meta-swupdate,sbabic/meta-swupdate