drm/amdgpu: fix typo error amdgput -> amdgpu

fix typo error:
change function name from "amdgput_ctx_total_num_entities" to
"amdgpu_ctx_total_num_entities".

Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>