Per definition, this function should return the number of bytes
consumed. Also take care of the unlikely case when buflen is not a
multiple of four; while transferring, the division cuts the remaining
bytes, so alter the return value accordingly.

Signed-off-by: Phil Sutter <n0-1@freewrt.org>
---
--- a/drivers/ata/pata_rb532_cf.c
+++ b/drivers/ata/pata_rb532_cf.c
@@ -88,7 +88,7 @@ static unsigned int rb532_pata_data_xfer
 		readsl(ioaddr, buf, buflen / sizeof(u32));
 
 	rb532_pata_finish_io(adev->link->ap);
-	return retlen;
+	return buflen - (buflen % sizeof(u32));;
 }
 
 static void rb532_pata_freeze(struct ata_port *ap)