which current and voltage do the LED strips need (5V, 2A would be something you could support with USB 2).
what output does the charger provide as a maximum? Is it enough to power both strips (5V and two times the A).
If these match it should work. Another topic could be the cable itself. Theoretically it could start to burn, if you try to channel to much current through it, but with simple USB I doubt it. If it is getting hot after some time, scrap your setup. This would be a fire hazard.