ARM: dts: msm: enable 11AD keep-radio-on-during-sleep on MSM8998

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: I04eed7802256c48ef9f39e7dc4e3b1a5386eb3c7
Signed-off-by: Maya Erez <merez@codeaurora.org>