drm/amdgpu: remove excess function parameter description

Fixes gcc warning:

drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c:431: warning: Excess function
parameter 'sw' description in 'vcn_v2_5_disable_clock_gating'
drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c:550: warning: Excess function
parameter 'sw' description in 'vcn_v2_5_enable_clock_gating'

Fixes: cbead2bd ("drm/amdgpu: add VCN2.5 VCPU start and stop")
Signed-off-by: yu kuai <yukuai3@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c

@@ -423,7 +423,6 @@ static void vcn_v2_5_mc_resume(struct amdgpu_device *adev)
  * vcn_v2_5_disable_clock_gating - disable VCN clock gating
  *
  * @adev: amdgpu_device pointer
- * @sw: enable SW clock gating
  *
  * Disable clock gating for VCN block
  */
@@ -542,7 +541,6 @@ static void vcn_v2_5_disable_clock_gating(struct amdgpu_device *adev)
  * vcn_v2_5_enable_clock_gating - enable VCN clock gating
  *
  * @adev: amdgpu_device pointer
- * @sw: enable SW clock gating
  *
  * Enable clock gating for VCN block
  */