Revert "ARM: dts: msm: enable WFI mode at boot"

This reverts commit 725c9e8e.
This change was made as 8939 was not booting when all low
power modes were enabled. Now the issue is fixed so we dont
need this change.

Change-Id: I42d06b671f2cc8815f8c2615bc56e2c91bd356a3
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>