JFS: Bio cleanup: Replace missing return statements

commit e30408b2 ("JFS: fix bio-related
build breakage") removed some "return 0;" statements, rather than
changing them to null returns.

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>