SamsungQualcommRIL: allow mQANElements to be device specific

The new RIL 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: I8a69bb6462552bf2374d963d82882315e8c77cef
SamsungQualcomm: Add support for Samsung's EMS dialing request

At least some samsungs require a specific emergency dial.
JF and D2 have been identified as _not_ requiring it, so it's
not for all Samsung qualcomms.

Change-Id: Id43728942f2d964a84f7486b1269d2da8305fdf6