Treblize input device config file location

Treblization requires to locate partner-specific configs in its own
partition. So the input device config file could be located in
/odm/usr or /vendor/usr.
This CL is to support those locations for the config.

Test: building succeeded and tested on sailfish.
Bug: 35815587
Change-Id: Ib6ae230118c8dc45dc030b32eb59441c3a544535