spi_bfin5xx: limit reaches -1

bfin_spi_flush() returns limit, which reaches -1 upon timeout.  but in
function bfin_spi_pump_transfers() it is compared with 0.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/spi/spi_bfin5xx.c

@@ -169,7 +169,7 @@ static int bfin_spi_flush(struct driver_data *drv_data)
 	unsigned long limit = loops_per_jiffy << 1;
 
 	/* wait for stop and clear stat */
-	while (!(read_STAT(drv_data) & BIT_STAT_SPIF) && limit--)
+	while (!(read_STAT(drv_data) & BIT_STAT_SPIF) && --limit)
 		cpu_relax();
 
 	write_STAT(drv_data, BIT_STAT_CLR);