clang: Pin clang/llvm/compiler-rt to specific revisions
clang: Pin clang/llvm/compiler-rt to specific revisions

Avoids frequent rebuilds these are active projects
and it takes a long time to compile. We will update them
weekly

Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

kraj/meta-clang,dsacre/meta-clang,kraj/meta-clang,kraj/meta-clang