Add Telefonica/Movistar specific APN details for dun

Movistar Spain needs to add a specific APN to offer tethering
in their devices.

Change-Id: I5554ff98a5ac4c5f33b9af0083e1fac8305c9e13
Signed-off-by: Albert <alberto.crespell@gmail.com>
Merge "Add Telefonica/Movistar specific APN details for dun" into du44