[bazel] llvm-config.h: Turn on LLVM_ENABLE_PLUGINS

Since #141650, `LLVM_ABI inline` has had different linkage regarding
to LLVM_ENABLE_PLUGINS. This doesn't intend Bazel build would
introduce plugins.

Author: chapuni

utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/llvm-config.h

@@ -124,6 +124,9 @@
 /* Define to 1 if you have the DIA SDK installed, and to 0 if you don't. */
 #define LLVM_ENABLE_DIA_SDK 0
 
+/* Define if plugins enabled */
+#define LLVM_ENABLE_PLUGINS
+
 /* Define if building LLVM with LLVM_ENABLE_TELEMETRY */
 #define LLVM_ENABLE_TELEMETRY 1