[SCSI] hpsa: add 5 second delay after doorbell reset

The hardware guys tell us that after initiating a software
reset via the doorbell register we need to wait 5 seconds before
attempting to talk to the board *at all*.  This means that we
cannot watch the board to verify it transitions from "ready" to
to "not ready" then back "ready", since this transition will
most likely happen during those 5 seconds (though we can still
verify the reset happens by watching the "driver version" field
get cleared.)

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>