QualcommSharedRIL: Disable radio power request on ril socket connect

Google introduced the code to send the radio power off as soon as
the ril socket is connected. Telephony sends Radio Power On
before the response for radio power off is received from QMI.
QMI cannot handle a RADIO_POWER request when there is a
pending request already.
Block this radio power off request to avoid this scenario.
Long term solution would be to check for any pending
radio power response before sending the radio power
request.

Change-Id: I9b77cd9f400e543f8768f501586e89863b6837b5