ARM: dts: msm: enable Synaptics touch controllers for 8939

8939 CDP supports three Synaptics touchscreen controllers : S3202,
S3408 and S3528. For S3202 and S3408, device tree support is
already there. This patch adds device tree configuration for
S3528 as well, to enable this touch controller on 8939.

Change-Id: Iead144fc420304983e88b5745c9e92039cab4871
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>