ARM: nhk8815_defconfig: Add new options

This adds some new driver options to the Nomadik NHK8815 defconfig:
- Activate IIO driver
- Enable CMA for coherent graphics allocations
- Activate DRM framebuffer driver for PL111
- Activate DRM panel driver for TPO TPG110
- Activate SPI GPIO driver (talks to the display)
- Activate STMPE PWM driver (used for display backlight)
- Activate PWM backlight
- Activate STw481x driver (PMIC)

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>