[pecoff] Use PATH_MAX instead of MAX_PATH

PATH_MAX is defined on all platforms while MAX_PATH is Windows-specific
diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
index 1883abe..302fb02 100644
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
@@ -889,7 +889,7 @@
     // At this moment we only have the base name of the DLL. The full path can
     // only be seen after the dynamic loading.  Our best guess is Try to get it
     // with the help of the object file's directory.
-    llvm::SmallString<MAX_PATH> dll_fullpath;
+    llvm::SmallString<PATH_MAX> dll_fullpath;
     FileSpec dll_specs(dll_name);
     dll_specs.GetDirectory().SetString(m_file.GetDirectory().GetCString());