Add BuildRequires on binutils-gold

While we *are* building the gold plugin, I noticed that we're
no longer running the tests for it on f41 and rawhide. Add a
BuildRequires on binutils-gold to restore the tests.

Author: nikic

llvm.spec

@@ -293,6 +293,7 @@ BuildRequires:	python%{python3_pkgversion}-myst-parser
 BuildRequires:	multilib-rpm-config
 %if %{with gold}
 BuildRequires:	binutils-devel
+BuildRequires:	binutils-gold
 %endif
 %ifarch %{valgrind_arches}
 # Enable extra functionality when run the LLVM JIT under valgrind.