orion_spi: fix handling of default transfer speed

Accept zero (the default!) as a per-transfer clock speed override.
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/spi/orion_spi.c

@@ -427,7 +427,7 @@ static int orion_spi_transfer(struct spi_device *spi, struct spi_message *m)
 			goto msg_rejected;
 		}
 
-		if (t->speed_hz < orion_spi->min_speed) {
+		if (t->speed_hz && t->speed_hz < orion_spi->min_speed) {
 			dev_err(&spi->dev,
 				"message rejected : "
 				"device min speed (%d Hz) exceeds "