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

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

Change-Id: Idac547d93e01d47ac80f9a5a28f7161a23034ba4
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>