defconfig: msm8974: Enable secure touch

Add CONFIG_SECURE_TOUCH to enable secure touch feature
in Atmel MXT driver.

Change-Id: I7df77d3d69e8afbc0e4cdb269e2f8bb81a7d24f3
Acked-by: Tony Hamilton <tonyh@qti.qualcomm.com>
Signed-off-by: Amy Maloche <amaloche@codeaurora.org>