Convert CONFIG_E300 et al to Kconfig

This converts the following to Kconfig:
   CONFIG_E300
   CONFIG_E5500

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/powerpc/cpu/mpc83xx/Kconfig b/arch/powerpc/cpu/mpc83xx/Kconfig
index 52bc8cf..2ebf8fc 100644
--- a/arch/powerpc/cpu/mpc83xx/Kconfig
+++ b/arch/powerpc/cpu/mpc83xx/Kconfig
@@ -1,6 +1,9 @@
 menu "mpc83xx CPU"
 	depends on MPC83xx
 
+config E300
+	def_bool y
+
 config SYS_CPU
 	default "mpc83xx"