spi: introduce master->handle_err() callback

This callback would be useful to handle an error that occurs in the generic
implementation of transfer_one_message(). The good candidate for this is to
drain FIFO and / or to terminate DMA transfers when timeout happened.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi.c

@@ -851,6 +851,9 @@ out:
 	if (msg->status == -EINPROGRESS)
 		msg->status = ret;
 
+	if (msg->status)
+		master->handle_err(master, msg);
+
 	spi_finalize_current_message(master);
 
 	return ret;