Provide API to retrive dual connected bandwidth

Provide API to retrive bandwidth per primary carrier
and secondary carrier

Bug: 162373679
Test: build, CTS, unit test
[1/1] com.android.internal.telephony.GsmCdmaPhoneTest#testEventLCEUpdate: PASSED (2.091s)

Merged-In: I1dc9f4e2a085cd26c3133a5c026971dbfc9145d7
Change-Id: I1dc9f4e2a085cd26c3133a5c026971dbfc9145d7