Bluetooth: stop proccessing malicious adv data

[ Upstream commit 3a56ef719f0b9682afb8a86d64b2399e36faa4e6 ]

Syzbot reported slab-out-of-bounds read in hci_le_adv_report_evt(). The
problem was in missing validaion check.

We should check if data is not malicious and we can read next data block.
If we won't check ptr validness, code can read a way beyond skb->end and
it can cause problems, of course.

Fixes: e95beb41 ("Bluetooth: hci_le_adv_report_evt code refactoring")
Reported-and-tested-by:  <syzbot+e3fcb9c4f3c2a931dc40@syzkaller.appspotmail.com>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>