[rilmodem][WIP] Removing showing of the call and volume interfaces in simless state

Decided to move online setting to upper layers. This is more in line
with ofono/doc/emergency-call-handling.txt. It also enables more
detailed error responses in UI if needed.

Signed-off-by: Jussi Kangas <jussi.kangas@oss.tieto.com>
[rilmodem][WIP] Enabling showing serial number in offline and simless state

Moving starting of device info interface already to rilmodem registration
phase. This enables checking the serial number always when ofono is on

Signed-off-by: Jussi Kangas <jussi.kangas@oss.tieto.com>
Merge pull request #47 from jkangas/master

Request for removing call and volume interfaces from simless state and adding showing the serial number from start