[lldb/Plugin] s/LLDB_PLUGIN/LLDB_PLUGIN_DEFINE/ (NFC)

Rename LLDB_PLUGIN to LLDB_PLUGIN_DEFINE as Pavel suggested in D73067 to
avoid name conflict.

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

@@ -51,7 +51,7 @@ using namespace lldb_private;
 using namespace elf;
 using namespace llvm::ELF;
 
-LLDB_PLUGIN(ObjectFileELF)
+LLDB_PLUGIN_DEFINE(ObjectFileELF)
 
 namespace {