ixgbe: Fix output from ixgbe_dump

I just found that when we had changed the Rx path to check for length
instead of the DD bit we introduced an issue in ixgbe_dump since we were no
longer clearing the status bits.

To correct this I am updating ixgbe_dump to look for the length bits in the
descriptor since that is what we are using in the Rx path.

Fixes: c3630cc4 ("ixgbe: Use length to determine if descriptor is done")
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>