ubifs: fix function pointer cast warnings

ubifs has a number of callback functions for ubifs_lpt_scan_nolock() using
two different prototypes, either passing a struct scan_data or
a struct ubifs_lp_stats, but the caller expects a void pointer instead.

clang-16 now warns about this:

fs/ubifs/find.c:170:9: error: cast from 'int (*)(struct ubifs_info *, const struct ubifs_lprops *, int, struct scan_data *)' to 'ubifs_lpt_scan_callback' (aka 'int (*)(struct ubifs_info *, const struct ubifs_lprops *, int, void *)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
  170 |                                     (ubifs_lpt_scan_callback)scan_for_dirty_cb,
      |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/ubifs/find.c:449:9: error: cast from 'int (*)(struct ubifs_info *, const struct ubifs_lprops *, int, struct scan_data *)' to 'ubifs_lpt_scan_callback' (aka 'int (*)(struct ubifs_info *, const struct ubifs_lprops *, int, void *)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
  449 |                                     (ubifs_lpt_scan_callback)scan_for_free_cb,
      |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Change all of these callback functions to actually take the void * argument
that is passed by their caller.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>