ARM: dts: msm: Add DLOAD cookie address to APQ8084

Specify DLOAD cookie base address in the 'android_usb' node.
This location is used by the DIAG USB driver to pass PID and
serial number information to bootloader when entering DLOAD mode.

Change-Id: I08b7ea0ddcaa512bedefa6cb37ba45c0159d7379
Signed-off-by: Jack Pham <jackp@codeaurora.org>