ext4: Remove code handling bio_alloc failure with __GFP_WAIT

Remove code handling bio_alloc failure with __GFP_WAIT.
GFP_NOIO implies __GFP_WAIT.

Signed-off-by: Nikanth Karthikesan <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

fs/ext4/extents.c

···
 			len = ee_len;
 
 		bio = bio_alloc(GFP_NOIO, len);
-		if (!bio)
-			return -ENOMEM;
 		bio->bi_sector = ee_pblock;
 		bio->bi_bdev   = inode->i_sb->s_bdev;