Here in America we use it to mean the same thing. A light/lighting fixture is wall or ceiling mounted.
The difference comes when we use one over the other. 'Lighting fixture' generally refers to a selection of light fixtures at a store that sells them.
Ex: "Home Depot has a huge selection of lighting fixtures"
Ex: To the clerk at Home Depot I'd say: "I want to buy that light fixture"
Ex: "I bought a new light fixture today"
Note: This isn't a fixed usage but generally this is how we think of it.