mm/rmap.c: remove redundant variable cend

Variable cend is set but never read, hence it is redundant and can be
removed.

Cleans up clang build warning: Value stored to 'cend' is never read

Link: http://lkml.kernel.org/r/20171011174942.1372-1-colin.king@canonical.com
Fixes: 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/rmap.c

@@ -899,7 +899,7 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
 	mmu_notifier_invalidate_range_start(vma->vm_mm, start, end);
 
 	while (page_vma_mapped_walk(&pvmw)) {
-		unsigned long cstart, cend;
+		unsigned long cstart;
 		int ret = 0;
 
 		cstart = address = pvmw.address;
@@ -915,7 +915,6 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
 			entry = pte_wrprotect(entry);
 			entry = pte_mkclean(entry);
 			set_pte_at(vma->vm_mm, address, pte, entry);
-			cend = cstart + PAGE_SIZE;
 			ret = 1;
 		} else {
 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
@@ -931,7 +930,6 @@ static bool page_mkclean_one(struct page *page, struct vm_area_struct *vma,
 			entry = pmd_mkclean(entry);
 			set_pmd_at(vma->vm_mm, address, pmd, entry);
 			cstart &= PMD_MASK;
-			cend = cstart + PMD_SIZE;
 			ret = 1;
 #else
 			/* unexpected pmd-mapped page? */