Use vma_pages function on vma object instead of explicit computation.
Found by coccinelle spatch "api/vma_pages.cocci"
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
                             unsigned long attrs)
 {
 #ifdef CONFIG_MMU
-       unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+       unsigned long user_count = vma_pages(vma);
        unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
        unsigned long off = vma->vm_pgoff;
        unsigned long pfn;