fs/hfsplus: use better @opf description

fs/hfsplus: use better @opf description

Use a more descriptive explanation of the @opf function parameter,
more in line with <linux/blk_types.h>.

Fixes: 02105f18a26c ("fs/hfsplus: wrapper.c: fix kernel-doc warnings")
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20240210050606.9182-1-rdunlap@infradead.org
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>