ARM: dts: msm: Enable the secure mem region for Spyro

Spyro need support Trusted UI, so enable the secure mem,
and set the size as 4M according to the display resolution.

Change-Id: I9fa0e100483e4de35852e6d7525fcc92f20a6140
Signed-off-by: Jiangjiang Shen <jiangjia@codeaurora.org>