Use newly introduced hidl_handle in DumpstateDefault

The dumpstate hal passes a hild_handle, but DumpstateDefault was
expecting a native_handle_t*.  This was exposed when
Id7dbc646b50f132e240bfbba719a2d36585ccc35 caused the Android.mk
file to be picked up.

Bug: 31982882
Bug: 32089785
Test: builds
Change-Id: I48c84b6d19a93ceb0641be517f378fd6aba45962