Fix comparison between hex and binary values

The verified boot hash in the attestation record is a binary blob, while
the property read from the system is a hex-encoded value.  Convert the
boot hash from the attestation record into hex before comparing.

Test: VtsHalKeymasterV4_0TargetTest
Bug: 130843899
Change-Id: I6f6e0da71501d741dd8b27d0778e1854af17ace6
1 file changed