[MIPS] Fix pcspeaker build.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/include/asm-mips/i8253.h b/include/asm-mips/i8253.h
index 032ca73..5dabc87 100644
--- a/include/asm-mips/i8253.h
+++ b/include/asm-mips/i8253.h
@@ -12,6 +12,8 @@
 #define PIT_CH0			0x40
 #define PIT_CH2			0x42
 
+#define PIT_TICK_RATE		1193182UL
+
 extern spinlock_t i8253_lock;
 
 extern void setup_pit_timer(void);