SUQ is a variant spelling, and these are generally frowned upon. The more standard spelling is SOUQ (that's what Wikipedia uses). However, the New York Times seems to prefer SOUK, so you might want to use that instead.
But this misses the main point: most solvers would only be familiar with SUQ/SOUQ/SOUK as a SCRABBLE word, if that. Until one of these Muslim marketplaces features prominently in an American movie/TV show, I'd personally only use it in a late week themeless puzzle.
