ksm: use find_mergeable_vma in try_to_merge_with_ksm_page

ksm: use find_mergeable_vma in try_to_merge_with_ksm_page

Doing the VM_MERGEABLE check after the page == kpage check won't provide
any meaningful benefit.  The !vma->anon_vma check of find_mergeable_vma is
the only superfluous bit in using find_mergeable_vma because the !PageAnon
check of try_to_merge_one_page() implicitly checks for that, but it still
looks cleaner to share the same find_mergeable_vma().

Signed-off-by: Andrea Arcangeli <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Cc: Petr Holasek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>