spi: axi-spi-engine: add watchdog timer

spi: axi-spi-engine: add watchdog timer

If there is an issue with the AXI SPI Engine hardware a scheduled
transfer might never be completed and spi_sync() will block forever.
This due to the uninterruptible wait for completion waiting for the
spi_finalize_current_message() that never comes.

Add a watchdog timer that will abort a transfer 5 seconds after it has
been started. This will potentially leave the hardware in a broken state
but it allows software to recover and allow to better diagnose the
underlying issue.

Co-developed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231204-axi-spi-engine-series-2-v1-9-063672323fce@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>