drm/amdgpu: fix IB alignment for UVD

According to the hw team, it should be 16, not 8.

Cc: Peter Fang <peter.fang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 4c8e68a..eab8d73 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -292,7 +292,7 @@
 			type = AMD_IP_BLOCK_TYPE_UVD;
 			ring_mask = adev->uvd.ring.ready ? 1 : 0;
 			ib_start_alignment = AMDGPU_GPU_PAGE_SIZE;
-			ib_size_alignment = 8;
+			ib_size_alignment = 16;
 			break;
 		case AMDGPU_HW_IP_VCE:
 			type = AMD_IP_BLOCK_TYPE_VCE;