ARM: dts: msm: Update msm-id format for APQ8084 Interposer

Update the APQ8084 Interposer device tree files to use the
split qcom,msm-id and qcom,board-id properties for matching
a device tree to a specific hardware type. Use the correct
platform subtype for identifying the interposer hardware.

Change-Id: I5cf126c89cf5ee91d5cf26397e749e06fe0dda24
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>