dt-binding: net: ti: am65x-cpts: fix dt_binding_check fail

Fix dt_binding_check fail:
Fix Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml: $id: relative path/filename doesn't match actual path or filename
	expected: http://devicetree.org/schemas/net/ti,k3-am654-cpts.yaml#
Unknown file referenced: [Errno 2] No such file or directory: '/usr/local/lib/python3.6/dist-packages/dtschema/schemas/net/ti,am654-cpts.yaml'
 Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml: $id: relative path/filename doesn't match actual path or filename
 expected: http://devicetree.org/schemas/net/ti,k3-am654-cpts.yaml#


Unknown file referenced: [Errno 2] No such file or directory: '/usr/local/lib/python3.6/dist-packages/dtschema/schemas/net/ti,am654-cpts.yaml'

Cc: Rob Herring <robh@kernel.org>
Fixes: 6e87ac74 ("dt-binding: ti: am65x: document common platform time sync cpts module")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>