ARM: dts: msm: Add USB dload cookie related device node on kona

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: I7536faa5a5583514388478662816e5f0801be20c
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>