drm/amd/amdgpu/cik_sdma: Fix a few incorrectly named functions

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

drivers/gpu/drm/amd/amdgpu/cik_sdma.c:735: warning: expecting prototype for cik_sdma_vm_copy_pages(). Prototype was for cik_sdma_vm_copy_pte() instead
drivers/gpu/drm/amd/amdgpu/cik_sdma.c:762: warning: expecting prototype for cik_sdma_vm_write_pages(). Prototype was for cik_sdma_vm_write_pte() instead
drivers/gpu/drm/amd/amdgpu/cik_sdma.c:792: warning: expecting prototype for cik_sdma_vm_set_pages(). Prototype was for cik_sdma_vm_set_pte_pde() instead
drivers/gpu/drm/amd/amdgpu/cik_sdma.c:814: warning: expecting prototype for cik_sdma_vm_pad_ib(). Prototype was for cik_sdma_ring_pad_ib() 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: Evan Quan <[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/cik_sdma.c

···
 }
 
 /**
- * cik_sdma_vm_copy_pages - update PTEs by copying them from the GART
+ * cik_sdma_vm_copy_pte - update PTEs by copying them from the GART
  *
  * @ib: indirect buffer to fill with commands
  * @pe: addr of the page entry
···
 }
 
 /**
- * cik_sdma_vm_write_pages - update PTEs by writing them manually
+ * cik_sdma_vm_write_pte - update PTEs by writing them manually
  *
  * @ib: indirect buffer to fill with commands
  * @pe: addr of the page entry
···
 }
 
 /**
- * cik_sdma_vm_set_pages - update the page tables using sDMA
+ * cik_sdma_vm_set_pte_pde - update the page tables using sDMA
  *
  * @ib: indirect buffer to fill with commands
  * @pe: addr of the page entry
···
 }
 
 /**
- * cik_sdma_vm_pad_ib - pad the IB to the required number of dw
+ * cik_sdma_ring_pad_ib - pad the IB to the required number of dw
  *
  * @ring: amdgpu_ring structure holding ring information
  * @ib: indirect buffer to fill with padding