Bluetooth: refactor malicious adv data check

Check for out-of-bound read was being performed at the end of while
num_reports loop, and would fill journal with false positives. Added
check to beginning of loop processing so that it doesn't get checked
after ptr has been advanced.

Signed-off-by: Brian Gix <brian.gix@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>