KeyMint: CreateKeyMintDevice retruns shared_ptr.

Fix reference counting by creating AndroidKeyMintDevice using
ndk::SharedRefBase::make instead of new.

Bug: 219791936
Test: atest keystore2_km_compat_test_cpp does not crash any more.
Change-Id: I4dfc9e8703ae5f51de5e8944d74157e9818bfe40
2 files changed