AMD does not furnish drivers for Mobility/laptop Ryzen APU's and graphics. These are the responsibility of the laptop manufacturer who customized the APU/ and graphics for a specific notebook.
Laptops do not have the features of desktop graphics cards. No ReLive/Wattman, etc.
You do not update the discrete graphics (Radeon 540)...you update the APU which furnishes the driver for the integrated and the discrete graphics.