ARM: dts: qcom: Add the modem PIL device for MSM8994

Add a device node to allow the PIL driver to probe the
modem device and bring the modem subsystem out of reset.

Change-Id: I95e0d38c4406292fb963b0a98cd279991e57f81e
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>