ARM: dts: msm: Add device tree node for ASM loopback

Add ASM loopback device tree node

Change-Id: I83ddea8742bb018c2bf456a3a0ea379f028d0a87
Signed-off-by: Vimal Puthanveed <vimalp@codeaurora.org>
Signed-off-by: flar2 <asegaert@gmail.com>