drm/amdgpu: fix some kernel-doc markups

Some functions have different names between their prototypes
and the kernel-doc markup.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>