drm/amd/amdgpu/gfx_v7_0: Repair function names in the documentation

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

 drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c:2126: warning: expecting prototype for gfx_v7_0_ring_emit_hdp(). Prototype was for gfx_v7_0_ring_emit_hdp_flush() instead
 drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c:2262: warning: expecting prototype for gfx_v7_0_ring_emit_ib(). Prototype was for gfx_v7_0_ring_emit_ib_gfx() instead
 drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c:3207: warning: expecting prototype for gfx_v7_0_ring_emit_vm_flush(). Prototype was for gfx_v7_0_ring_emit_pipeline_sync() instead

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: Sumit Semwal <sumit.semwal@linaro.org>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c

@@ -2116,7 +2116,7 @@ static int gfx_v7_0_ring_test_ring(struct amdgpu_ring *ring)
 }
 
 /**
- * gfx_v7_0_ring_emit_hdp - emit an hdp flush on the cp
+ * gfx_v7_0_ring_emit_hdp_flush - emit an hdp flush on the cp
  *
  * @ring: amdgpu_ring structure holding ring information
  *
@@ -2242,7 +2242,7 @@ static void gfx_v7_0_ring_emit_fence_compute(struct amdgpu_ring *ring,
  * IB stuff
  */
 /**
- * gfx_v7_0_ring_emit_ib - emit an IB (Indirect Buffer) on the ring
+ * gfx_v7_0_ring_emit_ib_gfx - emit an IB (Indirect Buffer) on the ring
  *
  * @ring: amdgpu_ring structure holding ring information
  * @job: job to retrieve vmid from
@@ -3196,7 +3196,7 @@ static int gfx_v7_0_cp_resume(struct amdgpu_device *adev)
 }
 
 /**
- * gfx_v7_0_ring_emit_vm_flush - cik vm flush using the CP
+ * gfx_v7_0_ring_emit_pipeline_sync - cik vm flush using the CP
  *
  * @ring: the ring to emit the commands to
  *