sif: BZ 4138: Fix a NULL pointer dereference in RDS during tear-down

sif: BZ 4138: Fix a NULL pointer dereference in RDS during tear-down

The issue is in the rqflush where the hardware view cannot be
trusted and SIF driver needs to rely on the software view. In
this case, software must wait for 1s to ensure that all the
completions are back. If the software counter is different
than the hardware view, the software counter will be used.

This issue is observed in Orabug: 23490618.

Signed-off-by: Wei Lin Guay <wei.lin.guay@oracle.com>
Reviewed-by: Knut Omang <knut.omang@oracle.com>