Updates for the RMI MIPS platform code

• set cache_coherent_dma flag in cpuinfo for XLR, this will make sure that BUS_DMA_COHERENT flag is handled correctly in busdma_machdep.c
• iodi.c, call device_get_name() just once
• clear RMI specific EIRR while intializing CPUs
• remove debug print in intr_machdep.c