SamsungExynos4RIL: buffer CAT Proactive Command

The RIL sends a CAT proactive command (init) before the registrant
is registered causing the command to be missed and STK menu to
not show up. Buffer it and fire it when the registrant is registered.

Change-Id: I021ce911e55b30c1a2d95d8060f7d9ff72e3b742
Merge remote-tracking branch 'cm/cm-11.0' into cm-11.0