ARM: dts: msm: add qcom,subsys-name for apr

Add qcom,subsys-name for apr. This property enables
apr to receive subsystem up/down notification from
modem/adsp.

Change-Id: I2887e08f560a1f2ff44a44f3c3b6ff553db86ee0
Signed-off-by: Meng Wang <mengw@codeaurora.org>