ARM: imx_v6_v7_defconfig: Select ADS7846 support

Add CONFIG_TOUCHSCREEN_ADS7846 support.
Signed-off-by: Diego Dorta <diego.dorta@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/configs/imx_v6_v7_defconfig

@@ -161,6 +161,7 @@ CONFIG_KEYBOARD_IMX=y
 CONFIG_MOUSE_PS2=m
 CONFIG_MOUSE_PS2_ELANTECH=y
 CONFIG_INPUT_TOUCHSCREEN=y
+CONFIG_TOUCHSCREEN_ADS7846=y
 CONFIG_TOUCHSCREEN_EGALAX=y
 CONFIG_TOUCHSCREEN_IMX6UL_TSC=y
 CONFIG_TOUCHSCREEN_EDT_FT5X06=y