MIPS: lantiq: enable oprofile support on lantiq targets

This patch sets the performance counters irq on Lantiq SoCs.

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3720/


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