[zorg][PowerPC] Don't checkout compiler-rt for runtime build

ClangBuilder will append all dependent projects to
DLLVM_ENABLE_PROJECTS, so we will get
'-DLLVM_ENABLE_PROJECTS=clang;compiler-rt;lld;llvm;clang-tools-extra'
-DLLVM_ENABLE_RUNTIMES=compiler-rt

This is breaking builds.
We shouldn't have compiler-rt in DLLVM_ENABLE_PROJECTS anymore.

Reviewed By: #powerpc, saghir, lei

Differential Revision: https://reviews.llvm.org/D90645
diff --git a/buildbot/osuosl/master/config/builders.py b/buildbot/osuosl/master/config/builders.py
index 15354ac..891f6ab 100644
--- a/buildbot/osuosl/master/config/builders.py
+++ b/buildbot/osuosl/master/config/builders.py
@@ -585,7 +585,7 @@
     'builddir': "clang-ppc64le-rhel",
     'factory' : ClangBuilder.getClangCMakeBuildFactory(clean=False,
                     checkout_clang_tools_extra=True,
-                    checkout_compiler_rt=True,
+                    checkout_compiler_rt=False,
                     checkout_lld=True,
                     checkout_libcxx=False,
                     useTwoStage=False,