octeontx2-af: Increase number of reserved entries in KPU

With current KPU profile, we have 2 reserved entries which can
be loaded from firmware to parse custom headers. Adding changes
to increase these reserved entries to 6.
And also removed KPU entries for unused LTYPEs like
NPC_LT_LA_IH_8_ETHER, NPC_LT_LA_IH_4_ETHER, NPC_LT_LA_IH_2_ETHER

Signed-off-by: Kiran Kumar K <kirankumark@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>