Currently, MBIM broadband Telit modem does not store firmware revision
into 'software_package_version', so it won't be possible to specialize
behavior based on modem model (using mm_telit_model_from_revision).
This change overloads load-revision in MBIM broadband Telit in order to
call parent's loading and store the returned 'caps_firmware_info' into
'software_package_version' via mm_shared_telit_store_revision.
b9ca16486e