Hide IBase static maps.

Because sizeof(IBase) can't be changed, we have a couple of maps to
store data about IBase. Hiding these maps internally inside libhidl* so
that we can more easily remove them in the future if necessary.

Fixes: 122472540
Test: hidl_test, checking logs
Change-Id: Ic722a9fd1f406cf03abb072015078fc7192066ce
4 files changed