Check all ports instead of just port_count ports. PTP init was only
checking ports 0 to port_count. If the hardware ports are not mapped
starting from 0 then they would be missed, e.g. if only ports 20-30 were
mapped it would attempt to init ports 0-10, resulting in NULL pointers
when attempting to timestamp. Now it will init all mapped ports.

Fixes: 70dfe25c ("net: sparx5: Update extraction/injection for timestamping")
Signed-off-by: Casper Andersson <casper.casan@gmail.com>
Reviewed-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>