libipt, block: add missing null checks

In pt_blk_proceed_no_event_cached(), we dereference the decoder and block
arguments.  Add NULL checks for them.

Change-Id: Ifca3c482ac9e3ac794e3cd875e0a24077766795f
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
1 file changed