packages/apps/Nfc: use proper nativehelper headers

libnativehelper exports headers under nativehelper. These were
available before incorrectly as global headers in order to give
access to jni.h.

Test: modules using packages/apps/Nfc find headers
Bug: 63762847
Change-Id: I494e04ba7112d41f18a4b9dba9495e5f9810be22