ARM: dts: msm: Add regulators for MM cfg slave devices on kona

In order to be able to vote on the MMCX regulator during the sequence of
connecting and disconnecting multimedia slaves, add node specific
regulator references.

Change-Id: If8a29d00d410263261f04ad12e7bf8fd6476c277
Signed-off-by: David Dai <daidavid1@codeaurora.org>