net/pcap: fix registration of timestamp dynamic field

net/pcap: fix registration of timestamp dynamic field

In pcap pmd, the timestamp mbuf dynamic field is mandatory. When the
pcap pmd is created in a secondary process (this is the case for pdump),
it cannot be registered because this is not allowed from a secondary
process.

To ensure that the field is properly registered, do it from probe()
instead of configure(). Indeed, probe() is first invoked on the primary
process when a device is created in a secondary, this enables
registering dynfield from secondary process.

Bugzilla ID: 571
Fixes: d23d73d088c1 ("net/pcap: switch Rx timestamp to dynamic mbuf field")

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>