ARM: shmobile: kzm9g: enable AS3711 PMIC in defconfig

An AS3711 PMIC is used on kzm9g to supply CPU power and LCD backlight.
This patch enables it in board defconfig.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>