dsymutil: Re-add missing -latomic (#85380)

This was accidentally removed in
https://reviews.llvm.org/D137799#4657404 /
https://reviews.llvm.org/D137799#C3933303OL44, and downstream projects
are forced to add it back. For example,
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=4e26331a5ee87928a16888c36d51e270f0f10f90

Fix this, by re-adding it.

Co-authored-by: MarcoFalke <*~=`'#}+{/-|&$^[email protected]>

Author: maflcko

llvm/tools/dsymutil/CMakeLists.txt

@@ -44,4 +44,4 @@ if(APPLE AND NOT LLVM_TOOL_LLVM_DRIVER_BUILD)
   target_link_libraries(dsymutil PRIVATE "-framework CoreFoundation")
 endif(APPLE AND NOT LLVM_TOOL_LLVM_DRIVER_BUILD)
 
-# target_link_libraries(dsymutil PRIVATE ${LLVM_ATOMIC_LIB})
+target_link_libraries(dsymutil PRIVATE ${LLVM_ATOMIC_LIB})