dt-bindings: net: ti: deprecate cpsw-phy-sel bindings

The cpsw-phy-sel driver was replaced with new PHY driver phy-gmii-sel, so
deprecate cpsw-phy-sel bindings.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

Documentation/devicetree/bindings/net/cpsw-phy-sel.txt

-TI CPSW Phy mode Selection Device Tree Bindings
+TI CPSW Phy mode Selection Device Tree Bindings (DEPRECATED)
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 Required properties: