net: thunderx: Fix TL4 configuration for secondary Qsets

TL4 calculation for a given SQ of secondary Qsets is incorrect
and goes out of bounds and also for some SQ's TL4 chosen will
transmit data via a different BGX interface and not same as
primary Qset's interface.

This patch fixes this issue.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>