drm/amd/amdgpu/sdma_v2_4: Correct misnamed function 'sdma_v2_4_ring_emit_hdp_flush()'

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

drivers/gpu/drm/amd/amdgpu/sdma_v2_4.c:281: warning: expecting prototype for sdma_v2_4_hdp_flush_ring_emit(). Prototype was for sdma_v2_4_ring_emit_hdp_flush() instead

Cc: Alex Deucher <[e-mail]>
Cc: "Christian König" <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: Sumit Semwal <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Lee Jones <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/sdma_v2_4.c

···
 }
 
 /**
- * sdma_v2_4_hdp_flush_ring_emit - emit an hdp flush on the DMA ring
+ * sdma_v2_4_ring_emit_hdp_flush - emit an hdp flush on the DMA ring
  *
  * @ring: amdgpu ring pointer
  *