drivers: qcom: Read command DB address/size from shared location

The command DB address on the RAM could change between builds. The AOP
stores this address in a dictionary that remains consistent for the
duration of a target. Read command DB address from this global location.

Change-Id: I37bfdc801156d14469d9048197b5957e64cf7dd5
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>