msm_bus: Check if cldata->pdata is null before access it

Since msm_bus_cldata may have empty pdata or handle member, add the
check before access it.

Change-Id: Ieed25b23f10e6cc67b7a8b714850e0acb2e6563b
Signed-off-by: Huang Yiwei <quic_hyiwei@quicinc.com>