mm/memory.c: fix spello of "function"

Fix typo/spello of "function".
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/e7bf180e-c558-b1d5-9a15-6d9708823c9c@infradead.orgSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memory.c

@@ -3764,7 +3764,7 @@ static vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
 
 /**
  * alloc_set_pte - setup new PTE entry for given page and add reverse page
- * mapping. If needed, the fucntion allocates page table or use pre-allocated.
+ * mapping. If needed, the function allocates page table or use pre-allocated.
  *
  * @vmf: fault environment
  * @page: page to map