Add getNumberOfModemsWithSimutaneousDataConnections.

It's a hidden API that indicates how many modems can have data
connection at the same time.

Bug: 92796390
Test: build
Change-Id: I9e0e8a2afed7ccc7b9cf9f397cd2e84486636217
Merged-In: I9e0e8a2afed7ccc7b9cf9f397cd2e84486636217
1 file changed