mm, hugetlb: trivial commenting fix

mm, hugetlb: trivial commenting fix

The name of the mutex written in comment is wrong.  Fix it.

Signed-off-by: Joonsoo Kim <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Hillf Danton <[email protected]>
Reviewed-by: Aneesh Kumar K.V <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: David Gibson <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>