[LLD] [COFF] Fix a condition that was missed in 7f0e6c31c2. NFC.

This should fix cases when e.g. auto import is enabled without
mingw mode in total being enabled.

Differential Revision: https://reviews.llvm.org/D89006

lld/COFF/SymbolTable.cpp

@@ -402,7 +402,7 @@ void SymbolTable::reportUnresolvable() {
     }
     if (name.contains("_PchSym_"))
       continue;
-    if (config->mingw && impSymbol(name))
+    if (config->autoImport && impSymbol(name))
       continue;
     undefs.insert(sym);
   }