mrsas: if controller reset is in progress, refrain from firing DCMDs to
firmware in shutdown

If controller reset is in progress, at same time if system shutdown is
issued then corresponding shutdown function in driver will be invoked
where driver is waiting 15 seconds to complete the controller reset.

If the reset is not complteted within that time frame driver will go
ahead and fire cache flush and shutdown DCMDs which will end up
accessing the the queues which are not initialized due to undergoing
reset leads to FMU error in firmware.

Fix:
In shutdown function, if controller reset is not finished within 15
seconds than driver will return to the OS without firing any DCMDs.

Reviewed by: imp
PR: 261375