cdx: Fix cdx_mmap_resource() after constifying attr in ->mmap()

Commit 94a20fb ("sysfs: treewide: constify attribute callback of
bin_attribute::mmap()") missed updating the attr parameter of
cdx_mmap_resource(), resulting in a build failure.

  drivers/cdx/cdx.c: In function 'cdx_create_res_attr':
  drivers/cdx/cdx.c:773:24: error: assignment to 'int (*)(struct file *, struct kobject *, const struct bin_attribute *, struct vm_area_struct *)' from incompatible pointer type 'int (*)(struct file *, struct kobject *, struct bin_attribute *, struct vm_area_struct *)' [-Wincompatible-pointer-types]
    773 |         res_attr->mmap = cdx_mmap_resource;
        |                        ^

Update cdx_mmap_resource() to match, resolving the build failure.

Fixes: 94a20fb ("sysfs: treewide: constify attribute callback of bin_attribute::mmap()")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Reviewed-by: Thomas Weißschuu <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20241107-sysfs-const-mmap-fix-cdx-v1-1-2ed9b7cd5f8b@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: nathanchance

drivers/cdx/cdx.c

@@ -707,7 +707,7 @@ static const struct vm_operations_struct cdx_phys_vm_ops = {
  * Return: true on success, false otherwise.
  */
 static int cdx_mmap_resource(struct file *fp, struct kobject *kobj,
-			     struct bin_attribute *attr,
+			     const struct bin_attribute *attr,
 			     struct vm_area_struct *vma)
 {
 	struct cdx_device *cdx_dev = to_cdx_device(kobj_to_dev(kobj));