dt-bindings: serial: samsung: Add apple,s5l-uart compatible

Apple mobile devices originally used Samsung SoCs (starting with the
S5L8900), and their current in-house SoCs continue to use compatible
UART peripherals. We'll call this UART variant apple,s5l-uart.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210304213902.83903-24-marcan@marcan.st


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