mm/huge_memory.c: fix "orig_pud" set but not used

Commit a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent
hugepages") introduced pudp_huge_get_and_clear_full() but no one uses
its return code.

In order to not diverge from pmdp_huge_get_and_clear_full(), just change
zap_huge_pud() to not assign the return value from
pudp_huge_get_and_clear_full().

mm/huge_memory.c: In function 'zap_huge_pud':
mm/huge_memory.c:1982:8: warning: variable 'orig_pud' set but not used [-Wunused-but-set-variable]
pud_t orig_pud;
^~~~~~~~

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Qian Cai <[e-mail]>
Reviewed-by: Andrew Morton <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

mm/huge_memory.c

···
 int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		 pud_t *pud, unsigned long addr)
 {
-	pud_t orig_pud;
 	spinlock_t *ptl;
 
 	ptl = __pud_trans_huge_lock(pud, vma);
···
 	 * pgtable_trans_huge_withdraw after finishing pudp related
 	 * operations.
 	 */
-	orig_pud = pudp_huge_get_and_clear_full(tlb->mm, addr, pud,
-			tlb->fullmm);
+	pudp_huge_get_and_clear_full(tlb->mm, addr, pud, tlb->fullmm);
 	tlb_remove_pud_tlb_entry(tlb, pud, addr);
 	if (vma_is_dax(vma)) {
 		spin_unlock(ptl);