[ObjC] Don't disallow vector parameters/return values in methods

whose introduced version is lower than the allowed version.

We should just rely on the target version as this introduced version can lead
to false positives (e.g. deprecated declarations).

rdar://31964333


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@302250 91177308-0d34-0410-b5e6-96231b3b80d8