MIPS Kprobes: Deny probes on ll/sc instructions

As ll/sc instruction are for atomic read-modify-write operations, allowing
probes on top of these insturctions is a bad idea.

Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2912/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>