LU-16667 build: fix extra errors related to struct mnt_idmap

LU-16667 build: fix extra errors related to struct mnt_idmap

This patch fixes the following extra build errors related to
struct mnt_idmap:

lustre/llite/pcc.c:2440:40: error: passing argument 1 of
'inode_owner_or_capable' from incompatible pointer type
[-Werror=incompatible-pointer-types]
 2440 |                 inode_owner_or_capable(&init_user_ns, inode)) ||
      |                                        ^~~~~~~~~~~~~
      |                                        |
      |                                        struct user_namespace *
include/linux/fs.h:1624:47: note: expected 'struct mnt_idmap *'
but argument is of type 'struct user_namespace *'
 1624 | bool inode_owner_or_capable(struct mnt_idmap *idmap,
      |                             ~~~~~~~~~~~~~~~~~~^~~~~
lustre/llite/pcc.c:3656:40: error: passing argument 1 of
'inode->i_op->fileattr_set' from incompatible pointer type
[-Werror=incompatible-pointer-types]
 3656 |         rc = inode->i_op->fileattr_set(&init_user_ns, dentry, &fa);
      |                                        ^~~~~~~~~~~~~
      |                                        |
      |                                        struct user_namespace *
lustre/llite/pcc.c:3656:40: note: expected 'struct mnt_idmap *'
but argument is of type 'struct user_namespace *'

Change-Id: Ia310f6f9053228b38b41243912dfe7818cfef33a
Test-Parameters: trivial
Fixes: 3011aa5 ("LU-16667 build: struct mnt_idmap, linux/filelock.h")
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/52955
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>