Portugal powers past weaker European equities

* Lisbon&aposs PSI-20 equity index outperforms to rise XX pct* Portuguese market buoyed by signs of economic recovery* FTSEurofirst 300 falls 0.3 pct to 1,343.23 points* Credit Suisse cuts Germany to "benchmark" vs "overweight"* Backdrop of M&A activity cushions stock marketsBy Sudip Kar-GuptaLONDON, May 6 (Reuters) - European stock markets fell broadly on Tuesday, apart from Lisbon which swam aga