powerpc: Add a Book-3E 64-bit defconfig

This defconfig's purpose at this time is to help catch compile errors
between Book-3S and Book-3E support in ppc64.  It is based on the
ppc64_defconfig with some things disabled that we dont support on
Book-3E right now (hugetlbfs, slices, etc.)

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>