radeon: use memcpy_to/fromio for UVD fw upload

I met a gpu addr bug recently and the kernel log
tells me the pc is memcpy/memset and link register is
radeon_uvd_resume.

As we know, in some architectures, optimized memcpy/memset
may not work well on device memory. Trival memcpy_toio/memset_io
can fix this problem.

BTW, amdgpu has already done it in:
commit ba0b2275 ("drm/amdgpu: use memcpy_to/fromio for UVD fw upload"),
that's why it has no this issue on the same gpu and platform.

Signed-off-by: Chen Li <chenli@uniontech.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>