[PATCH v2 2/6] dma/ioat: fix incorrectly set indexes after restart

[Walsh, Conor]

> As part of the process of restarting a dma instance, the IOAT driver
> will reset the HW addresses and state values. The read and write
> indexes for SW use need to be similarly reset to keep HW and SW in
> sync.
> 
> Fixes: 583f046dd404 ("dma/ioat: add start and stop")
> Cc: conor.walsh at intel.com
> Cc: stable at dpdk.org
> 
> Signed-off-by: Bruce Richardson <bruce.richardson at intel.com>

Reviewed-by: Conor Walsh <conor.walsh at intel.com>