Add max.active.modems system property into TelephonyProperties.sysprop am: ac709d1bc9

Change-Id: I739e29735f2594e3677f0fc58f5ae648e5bbc24a
tree: 4b267b3f401e304573f7e264b2fe0e7efee09b98
  1. srcs/
  2. OWNERS