libdm: fetch and present device status flags

Fetch detailed information for devices through its flags and store in
helper Info class, i.e.:
- active
- access
- activeTable
- inactiveTable
- bufferFull

Change-Id: I3241c5bca00e038d19f99390f40710ca7cff8456
Bug: 137759376
Test: manual test
Signed-off-by: Alessio Balsini <balsini@google.com>