ARM: dts: msm: add and use PMI8994 pin control boost regulator for msm8994

Add a new regulator for the PMI8994 Boost which controls the
audio pin control feature.  When this regulator is enabled, its
output voltage is determined by the state of the REQ_5V_BST pin.
If the pin signal is high, then the regulator outputs 5V.  If the
pin signal is low, then the regulator outputs VPH_PWR voltage.
This feature is intended to be used in conjunction with a codec
that toggles the REQ_5V_BST pin based upon the amplitude of the
audio signal to be output by the speakers.

Also, update audio codec device nodes in order to use this new
regulator.

Change-Id: Iffd6d457aee5ea00752fc57eb3ef4b73c8bb65ca
Signed-off-by: David Collins <collinsd@codeaurora.org>