drivers: soc: qcom: Add Command DB driver

Command DB is a database that provides a mapping between resource key
and the resource address for a system resource managed by RPMh. The
data is stored in a shared memory region and is loaded by the remote
processor.

The Command DB drivers exposes API for clients to query resource
parameters by a key string.

Change-Id: I1437d600006d86cfa69726d457435bad16132f75
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>