sh: defconfig: Drop obsolete CONFIG_NET_CLS_TCINDEX

This option was removed from Kconfig in 8c710f75 ("net/sched:
Retire tcindex classifier") but from the defconfigs.

Fixes: 8c710f75 ("net/sched: Retire tcindex classifier")
Signed-off-by: Johan Korsnes <johan.korsnes@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>