dt-bindings: mtd: spi-nor: add optional interrupts property

Some spi flash memories have an interrupt signal which can be used for
signalling on-chip events such as busy status or ecc errors to the host.

Add binding for "interrupts" property so that boards wiring this signal
may describe the connection.

Signed-off-by: Josua Mayer <josua@solid-run.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Acked-by: Michael Walle <mwalle@kernel.org>
Link: https://lore.kernel.org/r/20240219-mtd-flash-interrupt-binding-v7-1-206e30a656fa@solid-run.com


Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>