RIL: Add compatibility with qcom's DSDS

Devices with radio libraries built against a DSDS-enabled qualcomm
BSP (anything in the last 4 or 5 months, apparently) have a slight
incompatibility in the RIL protocol: it expects the first 4 bytes
of the datastream to be the slot's identification (even if the
device isn't dual-SIM). Absence of those 4 bytes will make the
connection hang.

Change-Id: I9f5821add02e7e5b5286c3b0818cb4a94edcc13c
Qualcomm LTE RILs: do not make mLteRsrp negative

  * In CM10.1, SignalStrength::validateInput() was added. This function expects
    mLteRsrp to be positive coming from the RIL.
  * Inverting in the RIL was causing validateInput() to flag mLteRsrp as invalid.
  * This shows up as a 0x7fffffff in About phone->Status->Signal strength when on LTE
  * Let validateInput() invert the sign instead of doing it in the custom RILs

Change-Id: I6ae7e4a56141c49628576305d21bee77b2a93ad7
QualcommSharedRIL: allow skipping pin/puk count

Change-Id: If2f046b7cfdec887fc9390a46c999c6acd763505