accel/qaic: Create a function to initialize BO

accel/qaic: Create a function to initialize BO

This makes sure that we have a single place to initialize and
re-initialize BO.

Use this new API to cleanup release_dbc()

We will need this for next patch to detach slicing to a BO.

Signed-off-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230901172247.11410-7-quic_jhugo@quicinc.com