bnxt_en: Configure ptp filters during bnxt open

For correctness, we need to configure the packet filters for timestamping
during bnxt_open.  This way they are always configured after firmware
reset or chip reset.  We should not assume that the filters will always
be retained across resets.

This patch modifies the ioctl handler and always configures the PTP
filters in the bnxt_open() path.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>