fs: add setlease to generic_ro_fops and read-only filesystem directory operations

fs: add setlease to generic_ro_fops and read-only filesystem directory operations

Add the setlease file_operation to generic_ro_fops, which covers file
operations for several read-only filesystems (BEFS, EFS, ISOFS, QNX4,
QNX6, CRAMFS, FREEVXFS). Also add setlease to the directory
file_operations for these filesystems.	A future patch will change the
default behavior to reject lease attempts with -EINVAL when there is no
setlease file operation defined. Add generic_setlease to retain the
ability to set leases on these filesystems.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260108-setlease-6-20-v1-1-ea4dec9b67fa@kernel.org
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>