ice: Always clear the QRXFLXP_CNTXT register for VF Rx queues

Currently when the PF reduces its number of channels via ethtool and
then VFs are created there may be stale data for some of the Rx queues
belonging to VFs. This happens when a VF reuses an Rx queue that was
previously used by the PF. Specifically, the QRXFLXP_CNTXT register
will have incorrect values. Fix this by always clearing the relevant
values in the QRXFLXP_CNTXT register for VF queues.

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>