MIPS: OCTEON: Use correct CSR to soft reset

Also delete unused cvmx_reset_octeon()
This fixes reboot for Octeon III boards

Signed-off-by: Chandrakala Chavva <cchavva@caviumnetworks.com>
Signed-off-by: Aleksey Makarov <aleksey.makarov@auriga.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/9471/


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