dt-bindings: serial: imx: Properly describe the i.MX1 interrupts

i.MX1 has three UART interrupts instead of a single one like other
i.MX devices.

Take this into account for properly describing the i.MX1 UART
interrupts.

This fixes the following dt-schema warning:

	from schema $id: http://devicetree.org/schemas/serial/fsl-imx-uart.yaml#yaml#



imx1-ads.dtb: serial@206000: interrupts: [[30], [29], [26]] is too long
Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231206162841.2326201-1-festevam@gmail.com


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