ice: remove unused struct member

The only time you can ever have a rq_last_status is if
a firmware event was somehow reporting a status on the receive
queue, which are generally firmware initiated events or
mailbox messages from a VF.  Mostly this struct member was unused.

Fix this problem by still printing the value of the field in a debug
print, but don't store the value forever in a struct, potentially
creating opportunities for callers to use the wrong struct member.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>