When a CDMA-only modem is registered with the EVDO network, its not possible to
read signal strength in the following cases:
1) while a data connection is active on single-AT-port modems, because the AT
port is used for PPP and not available for AT+CSQ, AT+CIND or vendor-specific
signal strength commands
2) when the modem reports only CDMA 1x signal strength with AT+CSQ
Now that we have a reasonable interpretation of RSSI from the QCDM
EVDO Pilot Sets V2 log messgae, use that when other means of getting
signal strength aren't available.
Dan Williams
5350b9f568