ARM: dts: msm: Add USB DLOAD cookie device node on QCS405

Linux USB DIAG driver needs to update PID and serial number with
IMEM memory to avoid DIAG port hopping while performing RAMDUMP
collection over USB. Hence add device node entry with IMEM
driver for USB dload cookie imem start address and size.

Change-Id: I8cb2a25bf642d39dd5c40b9d4c6874438298db30
Signed-off-by: Sriharsha Allenki <sallenki@codeaurora.org>