[CMake] NFC. Updating CMake dependency specifications

This patch updates a bunch of places where add_dependencies was being explicitly called to add dependencies on intrinsics_gen to instead use the DEPENDS named parameter. This cleanup is needed for a patch I'm working on to add a dependency debugging mode to the build system.

llvm-svn: 287206
diff --git a/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt b/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
index b3d26c4..a668ddb 100644
--- a/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
+++ b/llvm/lib/CodeGen/SelectionDAG/CMakeLists.txt
@@ -23,6 +23,7 @@
   SelectionDAGTargetInfo.cpp
   StatepointLowering.cpp
   TargetLowering.cpp
+  
+  DEPENDS
+  intrinsics_gen
   )
-
-add_dependencies(LLVMSelectionDAG intrinsics_gen)