Do not check with vendor vndk version

Current libcutils checks if memfd is supported with vendor VNDK version,
but this is no longer valid if VNDK is deprecated. As we can assume that
any vendor using this code is supported as long as it is treblelized,
simplify logic to check if memfd is valid to vendor only with
'ro.treble.enabled' property.

Bug: 290159430
Test: Cuttlefish with VNDK deprecated worked without error from
libcutils

Change-Id: I351f0798da99cb4827bc3e424b63a2eaee5c7461