drm/amd/amdgpu/jpeg_v2_0: Add some missing kernel-doc descriptions

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

 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c:498: warning: Function parameter or member 'addr' not described in 'jpeg_v2_0_dec_ring_emit_fence'
 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c:498: warning: Function parameter or member 'seq' not described in 'jpeg_v2_0_dec_ring_emit_fence'
 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c:498: warning: Function parameter or member 'flags' not described in 'jpeg_v2_0_dec_ring_emit_fence'
 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c:498: warning: Excess function parameter 'fence' description in 'jpeg_v2_0_dec_ring_emit_fence'
 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c:549: warning: Function parameter or member 'job' not described in 'jpeg_v2_0_dec_ring_emit_ib'
 drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c:549: warning: Function parameter or member 'flags' not described in 'jpeg_v2_0_dec_ring_emit_ib'

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/jpeg_v2_0.c

@@ -489,7 +489,9 @@ void jpeg_v2_0_dec_ring_insert_end(struct amdgpu_ring *ring)
  * jpeg_v2_0_dec_ring_emit_fence - emit an fence & trap command
  *
  * @ring: amdgpu_ring pointer
- * @fence: fence to emit
+ * @addr: address
+ * @seq: sequence number
+ * @flags: fence related flags
  *
  * Write a fence and a trap command to the ring.
  */
@@ -538,7 +540,9 @@ void jpeg_v2_0_dec_ring_emit_fence(struct amdgpu_ring *ring, u64 addr, u64 seq,
  * jpeg_v2_0_dec_ring_emit_ib - execute indirect buffer
  *
  * @ring: amdgpu_ring pointer
+ * @job: job to retrieve vmid from
  * @ib: indirect buffer to execute
+ * @flags: unused
  *
  * Write ring commands to execute the indirect buffer.
  */