arch: powerpc: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX

This option was removed from the Kconfig in commit
8c710f7 ("net/sched: Retire tcindex classifier") but it was not
removed from the defconfigs.

Fixes: 8c710f7 ("net/sched: Retire tcindex classifier")
Signed-off-by: Johan Korsnes <johan.korsnes@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250323191116.113482-1-johan.korsnes@gmail.com

Author: johankor

arch/powerpc/configs/ppc6xx_defconfig

@@ -252,7 +252,6 @@ CONFIG_NET_SCH_DSMARK=m
 CONFIG_NET_SCH_NETEM=m
 CONFIG_NET_SCH_INGRESS=m
 CONFIG_NET_CLS_BASIC=m
-CONFIG_NET_CLS_TCINDEX=m
 CONFIG_NET_CLS_ROUTE4=m
 CONFIG_NET_CLS_FW=m
 CONFIG_NET_CLS_U32=m