[AMDGPU][Flang] Adds MLIR as dependency

Since flang depends on MLIR, depend on MLIR for changes to catch
problems early.

buildbot/osuosl/master/config/builders.py

@@ -1948,7 +1948,7 @@
     'factory' : OpenMPBuilder.getOpenMPCMakeBuildFactory(
                         clean=True,
                         enable_runtimes=['compiler-rt', 'openmp', 'offload'],
-                        depends_on_projects=['llvm','clang','lld', 'offload', 'openmp','flang', 'compiler-rt'],
+                        depends_on_projects=['llvm','clang','lld', 'offload', 'openmp', 'mlir', 'flang', 'compiler-rt'],
                         extraCmakeArgs=[
                             "-DCMAKE_BUILD_TYPE=Release",
                             "-DCLANG_DEFAULT_LINKER=lld",