powerpc/40x: Update kilauea defconfig to support NAND, RTC and HWMON

This patch adds support for the following devices to the Kilauea
defconfig file:
- PPC4xx NAND controller (NDFC)
- I2C RTC (Dallas DS1338)
- I2C HWMON (Dallas DS1775)

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>