ARM: dts: msm: refactor smb138x device to its own dtsi

The smb138x device has been duplicated across many board level files.
Refactor the smb138x device to a separate dtsi file so it can be
included in any board level files.

Change-Id: I9520595f2a40e197ad2227a8391bed79412b19f8
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>