dev, arm: Refactor the NoMali GPU

dev, arm: Refactor the NoMali GPU

Refactor and cleanup the NoMaliGpu class:

  * Use a std::map instead of a switch block to map the parameter enum
    describing the GPU type to a NoMali type.

  * Remove redundant NoMali handle from the interrupt callback.

  * Make callbacks and API wrappers protected instead of private to
    enable future extensions.

  * Wrap remaining NoMali API calls.