dt-bindings: dma: ti: Add missing ti,k3-sci-common.yaml reference

The TI k3-bcdma and k3-pktdma both use 'ti,sci' and 'ti,sci-dev-id'
properties defined in ti,k3-sci-common.yaml. When 'unevaluatedProperties'
support is enabled, the follow warning is generated:

Documentation/devicetree/bindings/dma/ti/k3-bcdma.example.dt.yaml: dma-controller@485c0100: Unevaluated properties are not allowed ('ti,sci', 'ti,sci-dev-id' were unexpected)
Documentation/devicetree/bindings/dma/ti/k3-pktdma.example.dt.yaml: dma-controller@485c0000: Unevaluated properties are not allowed ('ti,sci', 'ti,sci-dev-id' were unexpected)

Add a reference to ti,k3-sci-common.yaml to fix this.

Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20211206174226.2298135-1-robh@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>