m68k: defconfig: Update defconfigs for v5.11-rc1

  - Enable modular build of netfilter nf_tables netdev REJECT support,
  - Enable modular build of the resource and cmdline API unit tests.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20201228104232.1421134-1-geert@linux-m68k.org