net/iavf: revert check for PF Rx timestamp support

net/iavf: revert check for PF Rx timestamp support

This reverts commit d21c2fe6e5a1ef1e7cc9490f54f359db1cfd5283.
While fixing an issue with enabling Rx timestamping on PFs which don't
report Rx timestamping, the offending commit broke PFs which do support
Rx timestamping.

Fixes: d21c2fe6e5a1 ("net/iavf: fix check for PF Rx timestamp support")
Suggested-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Soumyadeep Hore <soumyadeep.hore@intel.com>