aha1542: Fix bus reset

Bus reset always fails because aha1542_reset waits for the controller to assert
the INIT bit (Mailbox Initialization Required) which it never does. This bit is
asserted only after host reset.

Remove the requirement for INIT bit (we really need only the IDLE bit).

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>