[MIPS] Cobalt: clean up include files

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
diff --git a/arch/mips/cobalt/irq.c b/arch/mips/cobalt/irq.c
index fe93b84..950ad1e 100644
--- a/arch/mips/cobalt/irq.c
+++ b/arch/mips/cobalt/irq.c
@@ -17,7 +17,7 @@
 #include <asm/irq_cpu.h>
 #include <asm/gt64120.h>
 
-#include <asm/mach-cobalt/cobalt.h>
+#include <cobalt.h>
 
 /*
  * We have two types of interrupts that we handle, ones that come in through