MIPS: Octeon: Enable C0_UserLocal probing.

Octeon2 processor cores have a UserLocal register.  Remove the hard
coded negative probe and allow the standard probing to detect this
feature.

Signed-off-by: David Daney <david.daney@cavium.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2578/


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