MIPS: Loongson64: Adjust IRQ layout

Adjust IRQ layout in order to use IRQ resources more efficiently, which
is done by adjusting NR_IRQS and MIPS_CPU_IRQ_BASE.

Before this patch:
0~15:    ISA/LPC IRQs;
16~55:   Dynamic IRQs;
56~63:   MIPS CPU IRQs;
64~127:  PCH IRQs;
128~255: Dynamic IRQs.

After this patch:
0~15:    ISA/LPC IRQs;
16~23:   MIPS CPU IRQs;
24~87:   PCH IRQs;
88~280:  Dynamic IRQs.
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/mach-loongson64/irq.h

@@ -5,7 +5,11 @@
 #include <boot_param.h>
 
 /* cpu core interrupt numbers */
-#define MIPS_CPU_IRQ_BASE 56
+#define NR_IRQS_LEGACY		16
+#define NR_MIPS_CPU_IRQS	8
+#define NR_IRQS			(NR_IRQS_LEGACY + NR_MIPS_CPU_IRQS + 256)
+
+#define MIPS_CPU_IRQ_BASE 	NR_IRQS_LEGACY
 
 #include <asm/mach-generic/irq.h>