Allow keystore to read vendor security patch level.

The software KeyMint implementation used by km_compat needs to read the
vendor security patch level.

Bug: 189973657
Test: Android S GSI starts on rvc-vendor based devices.
      Also keystore2_km_compat_tests
Change-Id: I405d6a2b30fa2780321a3e209035c8f8283f5365
1 file changed