msm: board-ferrum: Add a dedicated DT_MACHINE for msmferrum

Add a new DT_MACHINE for msmferrum, which could support
dynamic selection of correct DT_MACHINE in runtime
according to device tree.

Change-Id: I203e714684361e7dabeef80b9ba4faa36bf13f44
Signed-off-by: Kishan Kumar <kishank@codeaurora.org>
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>