ixgbe: fix offloading bits when Rx bulk alloc is used

ixgbe: fix offloading bits when Rx bulk alloc is used

This is a fix for the ixgbe hardware offload flags not being set
when bulk alloc RX is used. The issue was caused by masking off
the bits that store the hardware offload values in the status_error
field to retrieve the done bit for the descriptor.

Commit 7431041062b9fd0555bac7ca4abebc99e3379fa5 in DPDK-1.3.0
introduced bulk dequeue, which included the bug.

Signed-off-by: Bryan Benson <bmbenson@amazon.com>
Acked-by: Ivan Boule <ivan.boule@6wind.com>