drm/amdgpu: fix two documentation mismatch issues

The function name mentioned in the documentational comments mismatches
the actual one. The mismatch may make trouble for automatic documentation
generation. One of the erronous name has seen to be misused
and fixed in commit bc5ab2d2 ("drm/amdgpu: fix typo in function
sdma_v4_0_page_resume").

There is apparently no functional change in the patch.

Signed-off-by: Wang Xiayang <xywang.sjtu@sjtu.edu.cn>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>