ARM: imx_v6_v7_defconfig: Eanble elan touch screen support

Currently, we just use driver elan_ts.c, not elants_i2c.c. So this
patch change this.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>

arch/arm/configs/imx_v6_v7_defconfig

@@ -183,6 +183,7 @@ CONFIG_TOUCHSCREEN_DA9052=y
 CONFIG_TOUCHSCREEN_EGALAX=y
 CONFIG_TOUCHSCREEN_GOODIX=y
 CONFIG_TOUCHSCREEN_ILI210X=y
+CONFIG_TOUCHSCREEN_ELAN_TS=y
 CONFIG_TOUCHSCREEN_MAX11801=y
 CONFIG_TOUCHSCREEN_IMX6UL_TSC=y
 CONFIG_TOUCHSCREEN_EDT_FT5X06=y