By Iain Rogers MADRID, April 2 (Reuters) - Debutants Malaga have toppled European giants AC Milan and Porto on their way to the Champions League quarter-finals and have another former winner in their sights when they host Borussia Dortmund on Wednesday. Coach Manuel Pellegrini and his players have propelled the Costa del Sol club to unprecedented success despite uncertainty over the commitment of their Qatari owner and cash-flow problems that prompted a ban from UEFA competition from next season. ... More...