Adapt for kernel 6.14

### Description The flag BLK_MQ_F_SHOULD_MERGE was removed in kernel 6.14 (see https://lore.kernel.org/linux-block/6880f851-bb7c-40a7-b405-ee9134b8bb1c@oracle.com/T/). This shall be adapted in file snapimage.c ### Usage tips * Please use the 👍 [reaction](https://blog.github.com/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/) to show that you are interested into this. * Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this. * Subscribe to receive notifications on status change and new comments, you can do also without add comment.