net: lan966x: debugfs: Fix showing the port keyset

On lan966x, it is possible to use debugfs to print different information
about the VCAPs. Information like, if it is enabled, how the ports are
configured, print the actual rules. The issue is that when printing how
the ports are configured for IS1 lookups, it was parsing the wrong
register to get this information. The fix consists in reading the
correct register that contains this information.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>