drm/amd/amdgpu/sdma_v6_0: Demote a bunch of half-completed function headers

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c:248: warning: Function parameter or member 'job' not described in 'sdma_v6_0_ring_emit_ib'
 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c:248: warning: Function parameter or member 'flags' not described in 'sdma_v6_0_ring_emit_ib'
 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c:945: warning: Function parameter or member 'timeout' not described in 'sdma_v6_0_ring_test_ib'
 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c:1124: warning: Function parameter or member 'ring' not described in 'sdma_v6_0_ring_pad_ib'
 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c:1175: warning: Function parameter or member 'vmid' not described in 'sdma_v6_0_ring_emit_vm_flush'
 drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c:1175: warning: Function parameter or member 'pd_addr' not described in 'sdma_v6_0_ring_emit_vm_flush'

Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v6_0.c

@@ -234,7 +234,7 @@ static void sdma_v6_0_ring_insert_nop(struct amdgpu_ring *ring, uint32_t count)
 			amdgpu_ring_write(ring, ring->funcs->nop);
 }
 
-/**
+/*
  * sdma_v6_0_ring_emit_ib - Schedule an IB on the DMA engine
  *
  * @ring: amdgpu ring pointer
@@ -937,7 +937,7 @@ static int sdma_v6_0_ring_test_ring(struct amdgpu_ring *ring)
 	return r;
 }
 
-/**
+/*
  * sdma_v6_0_ring_test_ib - test an IB on the DMA engine
  *
  * @ring: amdgpu_ring structure holding ring information
@@ -1119,7 +1119,7 @@ static void sdma_v6_0_vm_set_pte_pde(struct amdgpu_ib *ib,
 	ib->ptr[ib->length_dw++] = count - 1; /* number of entries */
 }
 
-/**
+/*
  * sdma_v6_0_ring_pad_ib - pad the IB
  * @ib: indirect buffer to fill with padding
  * @ring: amdgpu ring pointer
@@ -1168,7 +1168,7 @@ static void sdma_v6_0_ring_emit_pipeline_sync(struct amdgpu_ring *ring)
 			  SDMA_PKT_POLL_REGMEM_DW5_INTERVAL(4)); /* retry count, poll interval */
 }
 
-/**
+/*
  * sdma_v6_0_ring_emit_vm_flush - vm flush using sDMA
  *
  * @ring: amdgpu_ring pointer