ril: Unify network elements property check

frameworks/opt/telephony is using a slightly different named property
to check for the QANElements count.
Align the check here to the frameworks one to avoid redundancies.

Change-Id: I22f7cf070953026798d0ae4759e3c9845dba767c

ril/libril/ril.cpp

@@ -68,7 +68,7 @@ namespace android {
 #define ANDROID_WAKE_LOCK_USECS 200000
 
 #define PROPERTY_RIL_IMPL "gsm.version.ril-impl"
-#define PROPERTY_QAN_ELEMENTS "ro.ril.qanelements"
+#define PROPERTY_QAN_ELEMENTS "ro.ril.telephony.mqanelements"
 
 // match with constant in RIL.java
 #define MAX_COMMAND_BYTES (8 * 1024)