libata passthru: update cached device paramters

INIT_DEV_PARAMS and SET_MULTI_MODE change the device parameters cached
by libata.  Re-read IDENTIFY DEVICE info and update the cached device
paramters when seeing these commands.

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>