block/badblocks: fix badblocks loss when badblocks combine

hulk inclusion
category: bugfix
bugzilla: 188569, https://gitee.com/openeuler/kernel/issues/I6ZG5B


CVE: NA

--------------------------------

badblocks will loss if we set it as below:

  # echo 1 1 > bad_blocks
  # echo 3 1 > bad_blocks
  # echo 1 5 > bad_blocks
  # cat bad_blocks
    1 3

we will combine badblocks if there is an intersection between p[lo] and
p[hi] in badblocks_set(). The end of new badblocks is p[hi]'s end now. but
p[lo] may cross p[hi] and new end should be the larger of p[lo] and p[hi].
  lo: |------------------------|
  hi:		|--------|

Fixes: 9e0e252a ("badblocks: Add core badblock management code")
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>