ARM: dts: msm: add and configure boost bypass RPM regulator on MSM8994

To allow consumers to vote for boost bypass, add
the pmi8994_boostbypass regulator node.

Configure the boost-bypass regulator for use on MSM8994 boards.

Change-Id: I486281f1e9fdc07a674849043a3f4f06a42208e3
Signed-off-by: David Keitel <dkeitel@codeaurora.org>