cnss2: Use CONFIG_QCOM_COMMAND_DB to protect MSM command DB APIs

This makes sure CNSS2 driver is able to work in non-MSM platforms
which do not have command DB feature.

Change-Id: I9551bfc639e6db0256e475a27db5dec87bce74ed
Signed-off-by: Yue Ma <yuem@codeaurora.org>