ARM: dts: msm: Add SY8827 support for MSM8929 SKUL device

SY8827 is a buck regulator provides power for APC power rail in MSM8929
SKUL device. Add a device node for it and keep it as the primary power
supply for vdd-apc.

Change-Id: I0a70b4f26e59ffb51de951757819e3e88b8d77f7
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>