ARM: dts: msm: Change regulator names to match PMICs for MSM8992

Change the regulator names used for MSM8992 so that they match the
PMIC types that will be present. MSM8992 boards will be utilizing
PMICs PM8994 and PMI8994. In addition, add a stub regulator device
for PMI8994 boost-bypass regulator which is required for some devices
under PMI8994.

Change-Id: I9f57947f233796ac2fb09261995ca3a61df39353
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>