Move init and deinit of PTP support from open/close functions
to probe/remove funcs to avoid removing/re-adding of associated PTP
device(s) during ifup/ifdown.

v2: tg3_ptp_init call moved to correct place (thx. Prashant)
Signed-off-by: NIvan Vecera <ivecera@redhat.com>
Acked-by: NPrashant Sreedharan <prashant@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>