Display NEON in compiler string

if NEON intrinsics are being used and USE_NEON is defined.

closes https://github.com/official-stockfish/Stockfish/pull/3008

No functional change

src/misc.cpp

@@ -242,6 +242,9 @@ const std::string compiler_info() {
   #if defined(USE_MMX)
     compiler += " MMX";
   #endif
+  #if defined(USE_NEON)
+    compiler += " NEON";
+  #endif
 
   #if !defined(NDEBUG)
     compiler += " DEBUG";