We already has similar code in ext4_mb_complex_scan_group(), but
ext4_mb_simple_scan_group() still affected.

Other reports: https://www.spinics.net/lists/linux-ext4/msg60231.htmlReviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Dmitry Monakhov <dmonakhov@gmail.com>
Link: https://lore.kernel.org/r/20200310150156.641-1-dmonakhov@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>