[SCSI] arcmsr: Support HW reset for EH and polling scheme for scsi device

1. To support instantaneous report for SCSI device existing by periodic
   polling
2. In arcmsr_iop_xfer(), inform AP of F/W's deadlock state to prevent
   endless waiting
3. To block the coming SCSI command while the driver is handling bus reset
4. To support HW reset in bus reset error handler

Signed-off-by: Nick Cheng <nick.cheng@areca.com.tw>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>