ARM: dts: msm: Add proxy consumer properties for LD0 12 on apq8084

Add regulator proxy consumer properties for the regulators used
by HFPLL clock on apq8084 target.

Use proxy consumers to ensure that regulators is kept on during
boot-up at the highest allowed voltage.  This guarantees that any
hardware set up by bootloaders at non-minimum regulator voltage
will continue to operate until the driver responsible for the
hardware has initialized and made its own regulator requests.

Change-Id: Ic7a525fb7741cb4be5d94a184b2c2ce4d35a7abc
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>