soc: qcom: msm_bus: Remove panic for no aggregation scheme

Remove default panic error when no aggregation scheme is selected,
this is to support virtual fabrics that have no clocks or bandwidth
to aggregate.

Change-Id: I4fd8977845dd123890afc5076cd55499992e488e
Signed-off-by: David Dai <daidavid1@codeaurora.org>