hpsa: allow passthru ioctls to work with bidirectional commands

Treat the the data direction bits as a bit mask allowing both
READ and WRITE at the same time instead of testing for equality
to see if it's a exclusively a READ or a WRITE.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Reviewed-by: Mike Miller <michael.miller@canonical.com>
Reviewed-by: Webb Scales <webb.scales@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>