Fix compile warning, mostly struct/class inconsistency.

src/crypto/randomx/jit_compiler_x86.hpp

@@ -36,7 +36,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 namespace randomx {
 
 	class Program;
-	class ProgramConfiguration;
+	struct ProgramConfiguration;
 	class SuperscalarProgram;
 	class JitCompilerX86;
 	class Instruction;