BTA_DmAddDevice and BTM_SecAddDevice cleanup

BTM_SecAddDevice always return true, so get rid of return value.
BTA_DmAddDevice always passes empty device name, so get rid of it.
Parameters are packed and unpacked into message unnecesarly

BYPASS_INCLUSIVE_LANGUAGE_REASON=MITM is used through whole stack,
changing it just in one place would be confusing

Flag: exempt, no logical change, plus logging changes
Bug: 329458883
Test: mma -j32
Change-Id: I599293fc291d72d50f80a2eec5c094b47ea157ee