md/raid1: Fix data corruption for degraded array with slow disk

In the Linux kernel, the following vulnerability has been resolved: md/raid1: Fix data corruption for degraded array with slow disk read_balance() will avoid reading from slow disks as much as possible, however, if valid data only lands in slow disks, and a new normal disk is still in recovery, unrecovered data can be read: raid1_read_request read_balance raid1_should_read_first -> return false choose_best_rdev -> normal disk is not recovered, return -1 choose_bb_rdev -> missing the checking of recovery, return the normal disk -> read unrecovered data Root cause is that the checking of recovery is missing in choose_bb_rdev(). Hence add such checking to fix the problem. Also fix similar problem in choose_slow_rdev().