[SCSI] stex: Add reset code for st_yel (v2)

Add reset related code for st_yel.
1. Set the SS_H2I_INT_RESET bit.
2. Wait for the SS_MU_OPERATIONAL flag. This is also part of
   normal handshake process so move it to handshake routine.
3. Continue handshake with the firmware.

Signed-off-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>