drm/amdgpu/gfx10: fix wptr reset in KGQ init

wptr is a 64 bit value and we need to update the
full value, not just 32 bits. Align with what we
already do for KCQs.

Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Jesse Zhang <jesse.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit e80b1d1aa1)
Cc: stable@vger.kernel.org

drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c

@@ -6879,7 +6879,7 @@ static int gfx_v10_0_kgq_init_queue(struct amdgpu_ring *ring, bool reset)
 			memcpy_toio(mqd, adev->gfx.me.mqd_backup[mqd_idx], sizeof(*mqd));
 		/* reset the ring */
 		ring->wptr = 0;
-		*ring->wptr_cpu_addr = 0;
+		atomic64_set((atomic64_t *)ring->wptr_cpu_addr, 0);
 		amdgpu_ring_clear_ring(ring);
 	}