No more ashmem equivalent checker false alarm

The checker for ashmem file descriptor equivalency is
too strict and false alarms. This CL fix the issue.

Bug: 38352409
Test: successfully register multiple ashmem sensor direct channels
      without "Duplicate create channel request for the
      same share memory"

Change-Id: Ib80b47944940ce708953632855174d2f90c41b49