qcacmn: Add NULL check for 'pl_dev'

Currently 'pl_dev' is dereferenced without check for NULL in
get_pktlog_handle function in pktlog_internal.c

To address this issue add NULL check before dereferencing

Change-Id: Ic258db7bf1b404ff4f2d6c18abe775335074268b
CRs-Fixed: 2196058
1 file changed