drm/amd/amdgpu/ih_v6_0: Repair misspelling and provide descriptions for 'ih'

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

 drivers/gpu/drm/amd/amdgpu/ih_v6_0.c:392: warning: Function parameter or member 'ih' not described in 'ih_v6_0_get_wptr'
 drivers/gpu/drm/amd/amdgpu/ih_v6_0.c:432: warning: Function parameter or member 'ih' not described in 'ih_v6_0_irq_rearm'
 drivers/gpu/drm/amd/amdgpu/ih_v6_0.c:458: warning: Function parameter or member 'ih' not described in 'ih_v6_0_set_rptr'

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/ih_v6_0.c

@@ -119,7 +119,7 @@ force_update_wptr_for_self_int(struct amdgpu_device *adev,
  * ih_v6_0_toggle_ring_interrupts - toggle the interrupt ring buffer
  *
  * @adev: amdgpu_device pointer
- * @ih: amdgpu_ih_ring pointet
+ * @ih: amdgpu_ih_ring pointer
  * @enable: true - enable the interrupts, false - disable the interrupts
  *
  * Toggle the interrupt ring buffer (IH_V6_0)
@@ -381,6 +381,7 @@ static void ih_v6_0_irq_disable(struct amdgpu_device *adev)
  * ih_v6_0_get_wptr - get the IH ring buffer wptr
  *
  * @adev: amdgpu_device pointer
+ * @ih: amdgpu_ih_ring pointer
  *
  * Get the IH ring buffer wptr from either the register
  * or the writeback memory buffer.  Also check for
@@ -425,6 +426,7 @@ static u32 ih_v6_0_get_wptr(struct amdgpu_device *adev,
  * ih_v6_0_irq_rearm - rearm IRQ if lost
  *
  * @adev: amdgpu_device pointer
+ * @ih: amdgpu_ih_ring pointer
  *
  */
 static void ih_v6_0_irq_rearm(struct amdgpu_device *adev,
@@ -450,6 +452,7 @@ static void ih_v6_0_irq_rearm(struct amdgpu_device *adev,
  * ih_v6_0_set_rptr - set the IH ring buffer rptr
  *
  * @adev: amdgpu_device pointer
+ * @ih: amdgpu_ih_ring pointer
  *
  * Set the IH ring buffer rptr.
  */