drm/amdgpu: ih doorbell size of range changed for nbio v7.4

[Why]
nbio v7.4 size of ih doorbell range is 64 bit. This requires 2 DWords per register.

[How]
Change ih doorbell size from 2 to 4. This means two Dwords per ring.
Current configuration uses two ih rings.
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/nbio_v7_4.c

@@ -185,7 +185,7 @@ static void nbio_v7_4_ih_doorbell_range(struct amdgpu_device *adev,
 
 	if (use_doorbell) {
 		ih_doorbell_range = REG_SET_FIELD(ih_doorbell_range, BIF_IH_DOORBELL_RANGE, OFFSET, doorbell_index);
-		ih_doorbell_range = REG_SET_FIELD(ih_doorbell_range, BIF_IH_DOORBELL_RANGE, SIZE, 2);
+		ih_doorbell_range = REG_SET_FIELD(ih_doorbell_range, BIF_IH_DOORBELL_RANGE, SIZE, 4);
 	} else
 		ih_doorbell_range = REG_SET_FIELD(ih_doorbell_range, BIF_IH_DOORBELL_RANGE, SIZE, 0);