[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/Bitcode/Reader/CMakeLists.txt b/llvm/lib/Bitcode/Reader/CMakeLists.txt
index 62954f2..ca63f94 100644
--- a/llvm/lib/Bitcode/Reader/CMakeLists.txt
+++ b/llvm/lib/Bitcode/Reader/CMakeLists.txt
@@ -5,6 +5,7 @@
 
   ADDITIONAL_HEADER_DIRS
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Bitcode
-  )
 
-add_dependencies(LLVMBitReader intrinsics_gen)
+  DEPENDS
+  intrinsics_gen
+  )