dt-bindings: tegra: Add Apalis TK1 device tree binding documentation

Add the device tree binding documentation for Apalis TK1.

Note that this is using dashes aka '-' in compatible strings as
previously suggested by Rob.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Documentation/devicetree/bindings/arm/tegra.txt

@@ -32,6 +32,8 @@ board-specific compatible values:
   nvidia,whistler
   toradex,apalis_t30
   toradex,apalis_t30-eval
+  toradex,apalis-tk1
+  toradex,apalis-tk1-eval
   toradex,colibri_t20-512
   toradex,colibri_t30
   toradex,colibri_t30-eval-v3