SamsungQualcommRIL: allow mQANElements to be device specific

The new proprietary blobs for i9305 require that mQANElements = 6.
This patch simply introduces a new system property that can be used
to adjust the value of mQANElements if required.

Change-Id: I0a7d7dd4c6f7a17a808bbea2ac488be40e2a2d38
auto-merger: merge in from github/kk4.4