qed: Remove recursion in qed_aio_next_io()

Instead of calling itself recursively as the last thing, just convert
qed_aio_next_io() into a loop.

This patch is best reviewed with 'git show -w' because most of it is
just whitespace changes.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>

block/qed.c

@@ -1280,6 +1280,7 @@ static void qed_aio_next_io(QEDAIOCB *acb)
     size_t len;
     int ret;
 
+    while (1) {
         trace_qed_aio_next_io(s, acb, 0, acb->cur_pos + acb->cur_qiov.size);
 
         if (acb->backing_qiov) {
@@ -1318,7 +1319,7 @@ static void qed_aio_next_io(QEDAIOCB *acb)
             }
             return;
         }
-    qed_aio_next_io(acb);
+    }
 }
 
 static BlockAIOCB *qed_aio_setup(BlockDriverState *bs,