[Bugfix][T106ZXW-91][Network]  add qser_nw_get_signal_strength API in demo

       Affected branch: unknown
       Affected module: unknown
       Is it affected on both ZXIC and MTK:ZXIC only
       Self-test: Yes
       Doc Update: No

Change-Id: I3a3ba5e6c2ff9ff9d66778ce8bc933febd52f068
1 file changed