sil24 softreset timeout was > 100ms (100 loops with msleep(1)), which
turned out to be too short for some devices (ASI ARAID99 2000).  This
patch converts sil24 softreset waiting loop to use proper timeout
condition and lengthen the timeout to ATA_TMOUT_BOOT secs and check
interval to 100ms.  Chisato Yamauchi discovered the problem and
supplied initial patch.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Chisato Yamauchi <cyamauch@plamo.linet.gr.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>