mm/vmscan: fix comments for isolate_lru_page()

fix comments for isolate_lru_page():
s/fundamentnal/fundamental
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200927173923.GA8058@rlkSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c

@@ -1754,7 +1754,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
  * Restrictions:
  *
  * (1) Must be called with an elevated refcount on the page. This is a
- *     fundamentnal difference from isolate_lru_pages (which is called
+ *     fundamental difference from isolate_lru_pages (which is called
  *     without a stable reference).
  * (2) the lru_lock must not be held.
  * (3) interrupts must be enabled.