clocksource: convert footbridge to generic i8253 clocksource

Convert the footbridge isa-timer code to use generic i8253 clocksource.

Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/i8253.h b/arch/arm/include/asm/i8253.h
new file mode 100644
index 0000000..70656b6
--- /dev/null
+++ b/arch/arm/include/asm/i8253.h
@@ -0,0 +1,15 @@
+#ifndef __ASMARM_I8253_H
+#define __ASMARM_I8253_H
+
+/* i8253A PIT registers */
+#define PIT_MODE	0x43
+#define PIT_CH0		0x40
+
+#define PIT_LATCH	((PIT_TICK_RATE + HZ / 2) / HZ)
+
+extern raw_spinlock_t i8253_lock;
+
+#define outb_pit	outb_p
+#define inb_pit		inb_p
+
+#endif