powerpc: Rename e55xx_smp_defconfig to corenet64_smp_defconfig

Rather than trying to use the core name we use corenet to distinquish
the platform/core combo.  corenet64 will be a 64-bit kernel build and
we'll add a new defconfig for corenet32 for a 32-bit platforms.

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

diff --git a/arch/powerpc/configs/e55xx_smp_defconfig b/arch/powerpc/configs/corenet64_smp_defconfig
similarity index 100%
rename from arch/powerpc/configs/e55xx_smp_defconfig
rename to arch/powerpc/configs/corenet64_smp_defconfig