iomap: fix the comment describing IOMAP_NOWAIT

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

include/linux/iomap.h

@@ -59,7 +59,7 @@ struct iomap {
 #define IOMAP_REPORT		(1 << 2) /* report extent status, e.g. FIEMAP */
 #define IOMAP_FAULT		(1 << 3) /* mapping for page fault */
 #define IOMAP_DIRECT		(1 << 4) /* direct I/O */
-#define IOMAP_NOWAIT		(1 << 5) /* Don't wait for writeback */
+#define IOMAP_NOWAIT		(1 << 5) /* do not block */
 
 struct iomap_ops {
 	/*