galaxys2: add opensource libril, remove ril class

- remove blob rild
- remove blob libril.so

Change-Id: I9f6d99bbd0ecf7c591c64a53e738339f0eaa3905
galaxys2: switch to smdk4412 kernel

Change-Id: I9b4ee389937a6418bb9de79679324aae40a9a736
galaxys2: libril: add a fallback to handle signalstrength for older modems

Change-Id: I66c253dbd8bf0db38b7e723cd43357752d2d9949