dt-bindings: serial: amlogic,meson-uart: Add compatible string for T7

Amlogic T7 SoCs uses the same UART controller as S4 SoCs and G12A.
There is no need for an extra compatible line in the driver, but
add T7 compatible line for documentation.

Signed-off-by: Lucas Tanure <tanure@linux.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230814080128.143613-1-tanure@linux.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>