octeontx2-af: Reset PTP config in FLR handler

Upon receiving ptp config request from netdev interface , Octeontx2 MAC
block CGX is configured to append timestamp to every incoming packet
and NPC config is updated with DMAC offset change.

Currently this configuration is not reset in FLR handler. This patch
resets the same.

Signed-off-by: Harman Kalra <hkalra@marvell.com>
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>