[PATCH] sil24: use SRST for phy_reset

There seems to be no way to obtain device signature from sil24 after
SATA phy reset and SRST is needed anyway for later port multiplier
suppport.  This patch converts sil24_phy_reset to use SRST instaed.

Signed-off-by: Tejun Heo <htejun@gmail.com>
--

Jeff, I didn't remove the 10ms sleep just to be on the safe side.  I
think we can live with 10ms sleep on SRST.
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>