drm/amdgpu/vcn: re-use original vcn0 doorbell value

root cause that S2A need to use deduct offset flag.
after setting this flag, vcn0 doorbell value works.
so return it as before
Signed-off-by: Jane Jian <Jane.Jian@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/mmsch_v4_0.h

@@ -32,7 +32,6 @@
 
 #define RB_ENABLED (1 << 0)
 #define RB4_ENABLED (1 << 1)
-#define MMSCH_DOORBELL_OFFSET 0x8
 
 #define MMSCH_VF_ENGINE_STATUS__PASS 0x1
 

drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c

@@ -100,7 +100,6 @@ static int vcn_v4_0_sw_init(void *handle)
 	struct amdgpu_ring *ring;
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 	int i, r;
-	int vcn_doorbell_index = 0;
 
 	r = amdgpu_vcn_sw_init(adev);
 	if (r)
@@ -112,12 +111,6 @@ static int vcn_v4_0_sw_init(void *handle)
 	if (r)
 		return r;
 
-	if (amdgpu_sriov_vf(adev)) {
-		vcn_doorbell_index = adev->doorbell_index.vcn.vcn_ring0_1 - MMSCH_DOORBELL_OFFSET;
-		/* get DWORD offset */
-		vcn_doorbell_index = vcn_doorbell_index << 1;
-	}
-
 	for (i = 0; i < adev->vcn.num_vcn_inst; i++) {
 		volatile struct amdgpu_vcn4_fw_shared *fw_shared;
 
@@ -135,7 +128,7 @@ static int vcn_v4_0_sw_init(void *handle)
 		ring = &adev->vcn.inst[i].ring_enc[0];
 		ring->use_doorbell = true;
 		if (amdgpu_sriov_vf(adev))
-			ring->doorbell_index = vcn_doorbell_index + i * (adev->vcn.num_enc_rings + 1) + 1;
+			ring->doorbell_index = (adev->doorbell_index.vcn.vcn_ring0_1 << 1) + i * (adev->vcn.num_enc_rings + 1) + 1;
 		else
 			ring->doorbell_index = (adev->doorbell_index.vcn.vcn_ring0_1 << 1) + 2 + 8 * i;