drm/amdgpu/vce1: Implement VCE1 IP block (v2)

drm/amdgpu/vce1: Implement VCE1 IP block (v2)

Implement the necessary functionality to support the VCE1.
This implementation is based on:

- VCE2 code from amdgpu
- VCE1 code from radeon (the old driver)
- Some trial and error

A subsequent commit will ensure correct mapping for
the VCPU BO, which will make this actually work.

v2:
- Use memset_io more.
- Use memcpy_toio more.
- Remove __func__ from warnings.
- Don't reserve and map the VCPU BO anymore.
- Add empty line to multi-line comments

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Co-developed-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Signed-off-by: Alexandre Demers <alexandre.f.demers@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>