The owner module reference of the ahci platform's scsi_host is
initialized to libahci_platform's one, because these drivers use a
scsi_host_template defined in libahci_platform.  So these drivers can
be unloaded even if the scsi device is being accessed.

This fixes it by pushing the scsi_host_template from libahci_platform
to all leaf drivers.  The scsi_host_template is passed through a new
argument of ahci_platform_init_host().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-ide@vger.kernel.org
Cc: linux-scsi@vger.kernel.org