ARM: imx_v6_v7_defconfig: add POWER_RESET_SYSCON

Add POWER_RESET_SYSCON since Vybrid SoC's now make use of this
driver to provide software reset capabilities through the SRC
module.

Also regenerated using savedefconfig which removed the config
BACKLIGHT_LCD_SUPPORT which is now selected by default since
commit 9c8ee3c7 ("video: mx3fb: always enable
BACKLIGHT_LCD_SUPPORT").

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>