lsi: pass lsi_request to lsi_reselect

All callers of lsi_reselect have a lsi_request struct at hand anyway.
So just pass it directly instead of having lsi_reselect search for it
using the tag.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>