ARM: dts: msm: add bootargs in device tree for 2 cores boot on 8936

Add boot args in device tree to support cold booting 2 cores
configuration on 8936. This helps in keeping the cold boot
temperatures under control. Rest of the cores will be released
post boot.

Change-Id: Ibe4867c16ba6d4805eca98c7a4aee1f1cb8aaceb
Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>