Hi Guru,
I haven't worked on MobileIron MDM, so not sure how to set the configuration file for Fiori client. But as an alternative you can create your own custom Fiori client using Kapsel plugin as explained here:Getting Started with Kapsel - Part 14 -- SAP Fiori Client (New in SP04) . Hence you can set the configuration properties from the code like Fiori URL and passcode policy.
Information on SMP SDK download : Download and install Mobile SDK SP04
Regards,
Midhun VP