Make ScriptParser::checkSection a non-member function.
Make ScriptParser::checkSection a non-member function.

This patch also make its return type to `void` because
it always returns a given value as-is.

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@315165 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld