msm: smd_tty: add new SMD TTY port

Add new port for exporting DATA4 (ATCoP) to userspace.

CRs-Fixed: 519977
Change-Id: I63f79788ff06a00c3aead4a725039ae14feb020f
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>
Merge "msm: smd_tty: add new SMD TTY port"