drm/amdgpu: IH process reset count when restart

Otherwise when IH process restart, count is zero, the loop will
not exit to wake_up_all after processing AMDGPU_IH_MAX_NUM_IVS
interrupts.

Cc: stable@vger.kernel.org
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -223,7 +223,7 @@ int amdgpu_ih_wait_on_checkpoint_process(struct amdgpu_device *adev,
  */
 int amdgpu_ih_process(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih)
 {
-	unsigned int count = AMDGPU_IH_MAX_NUM_IVS;
+	unsigned int count;
 	u32 wptr;
 
 	if (!ih->enabled || adev->shutdown)
@@ -232,6 +232,7 @@ int amdgpu_ih_process(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih)
 	wptr = amdgpu_ih_get_wptr(adev, ih);
 
 restart_ih:
+	count  = AMDGPU_IH_MAX_NUM_IVS;
 	DRM_DEBUG("%s: rptr %d, wptr %d\n", __func__, ih->rptr, wptr);
 
 	/* Order reading of wptr vs. reading of IH ring data */