ARM: versatile: select some defaults in defconfig

This updates the Versatile defconfig to:
- Use NO_HZ_IDLE and HIGH_RES_TIMERS
- Enable the I2C driver
- Enable the SPI driver
- Enable the RTC driver for DS1338 as found on the Versatile
  boards
- Compile in the MMCI MMC driver, which is good if you
  want to mount a root FS on the MMC card without having
  to first load this module from an initramfs

Patch tested on the Versatile AB, QEMU for Versatile AB
and QEMU for Versatile PB.

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>