PFW: support to load the config policy from vendor partition

For treble compliance, loading the config policy from vendor partition
should be supported.

Bug: 80626872
Test: audio works normally with USE_CONFIGURABLE_AUDIO_POLICY set
Change-Id: I7fec31346b80874c323556e28debb4a0888b27e6
Signed-off-by: Mingwei Shi <mingwei.shi@intel.com>
Signed-off-by: Qin, Xiaokang <xiaokang.qin@intel.com>
(cherry picked from commit 955e35cb670ff210535be268aa3589d68d92b148)