reduce defconfig to a fragment

As part of the cpufreq driver work, I was looking at the
arch/arm/configs/nintendo3ds_defconfig thinking "that's way larger than
it should be."  Not that we're selecting more than we need (always a
possibility), but because the defconfigs under arch/{arch}/configs/ are
usually fragments.

To update a defconfig, you sould do:

1. Generate .config:
$ ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- make -j$(nproc) \
  nintendo3ds_defconfig

2. Update configs via menuconfig:
$ ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- make -j$(nproc) \
  menuconfig
<use y,n,m to select yes, no, module. / to search, Esc to get out, make
sure to save>

3. Generate defconfig diff:
$ ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- make -j$(nproc) \
  savedefconfig

4. Update nintendo3ds_defconfig:
$ cp defconfig arch/arm/configs/nintendo3ds_defconfig

Signed-off-by: Nick Desaulniers <[email protected]>