ARM: imx_v6_v7_defconfig: Select hid-multitouchdriver

Select CONFIG_HID_MULTITOUCH so that we can have multi touchscreen
funtionality via USB by default on Engicam i.CoreM6 Quad with
OpenFrame Cap 10.1 display boards.

Cc: Matteo Lisi <matteo.lisi@engicam.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>