ARM: dts: msm: add speaker boost regulator device for msmsamarium-mtp

Add a fixed regulator device which controls the 5 V boost
regulator found on msmsamarium-mtp boards using PMA8084 GPIO 1.
This regulator powers the speaker found on the board.

Change-Id: I62cf2425e066031bb2a82257a9f320d69c974dcd
Signed-off-by: David Collins <collinsd@codeaurora.org>