Boards like TinkerBoard (RK3288) have a Video Processing Unit. Is that a physical chip? It's inside the Mali GPU? Or it's a virtual thing?
Modern mobile platforms are generally single chip devices. The CPU, GPU, video encode/decode, display, and memory controller are all part of the same physical chip. In many cases the modems for cellular connectivity and WiFi are also part of the same chip, but they are sometimes separate.
Inside the chip the VPU is a different processor to the Mali GPU.
So it's an independent chip inside the Mali GPU right? Or for processor you mean it's virtual?
The Mali GPU is not a physical chip in its own right, it's one logical component inside the full system-on-a-chip silicon die.
For example, see this teardown of a Samsung chip containing a Mali GPU: https://www.techinsights.com/about-techinsights/overview/blog/samsung-galaxy-s9-teardown/
The VPU is an independent component to the GPU, yes.