dt-bindings: arm: amlogic: add MeCool KII/KIII Pro bindings

Add the board bindings for the MeCool (Videostrong Technology Co., Ltd)
KII-Pro (S905D) and KIII-Pro (S912) devices.

Signed-off-by: Christian Hewitt <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Kevin Hilman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/devicetree/bindings/arm/amlogic.yaml

···
               - libretech,aml-s905d-pc
               - phicomm,n1
               - smartlabs,sml5442tw
+              - videostrong,gxl-kii-pro
           - const: amlogic,s905d
           - const: amlogic,meson-gxl
 
···
               - minix,neo-u9h
               - nexbox,a1
               - tronsmart,vega-s96
+              - videostrong,gxm-kiii-pro
               - wetek,core2
           - const: amlogic,s912
           - const: amlogic,meson-gxm