m68k/defconfig: Make NFS_V4 modular instead of builtin

This reduces the kernel image size by ca. 100 KiB, while still allowing
NFS root.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

diff --cc arch/m68k/configs/amiga_defconfig
Simple merge

diff --cc arch/m68k/configs/apollo_defconfig
Simple merge

diff --cc arch/m68k/configs/atari_defconfig
Simple merge

diff --cc arch/m68k/configs/bvme6000_defconfig
Simple merge

diff --cc arch/m68k/configs/hp300_defconfig
Simple merge

diff --cc arch/m68k/configs/mac_defconfig
Simple merge

diff --cc arch/m68k/configs/multi_defconfig
Simple merge

diff --cc arch/m68k/configs/mvme147_defconfig
Simple merge

diff --cc arch/m68k/configs/mvme16x_defconfig
Simple merge

diff --cc arch/m68k/configs/q40_defconfig
Simple merge

diff --cc arch/m68k/configs/sun3_defconfig
Simple merge

diff --cc arch/m68k/configs/sun3x_defconfig
Simple merge