ARM: dts: msm: enable 11AD keep-radio-on-during-sleep on SM8150

keep_radio_on_during_sleep allows reserving the 11AD connections
during suspend.
In such a case PCIe will suspend to D3hot and the device power
will not be turned off.

Change-Id: I021373d1475f5f5517ac65e30268efae1e414579
Signed-off-by: Maya Erez <merez@codeaurora.org>