MIPS: Netlogic: SMP fixes for XLR/XLS platform code.
Fix few issues in the Netlogic code:
- Use handle_percpu_irq to handle per-cpu interrupts
- Remove unused function nlm_common_ipi_handler()
- Call scheduler_ipi() on SMP_RESCHEDULE_YOURSELF
- Enable interrupts in nlm_smp_finish()