I have the same problem here with a couple of brand new DL380 G7's.
I also reinstalled a DL380 G7 (which was running vSphere 5.0 without warnings) to vSphere 5.1, and now there is the same warning on the SmartArray p410i.
'/opt/hp/hpacucli/bin/hpacucli controller all show config detail' on each host reports no problems.
However running 'esxcfg-scsidevs -l' shows 'Status: degraded' on both vSphere 5.0 and vSphere 5. !!!
Perhaps the warning was always there but is being displayed since the last version of the driver?