[MIPS] time: Code cleanups

* Do not include unnecessary headers.
* Do not mention time.README.
* Do not mention mips_timer_ack.
* Make clocksource_mips static.  It is now dedicated to c0_timer.
* Initialize clocksource_mips.read statically.
* Remove null_hpt_read.
* Remove an argument of plat_timer_setup.  It is just a placeholder.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/qemu/q-irq.c b/arch/mips/qemu/q-irq.c
index 4681757..11f9847 100644
--- a/arch/mips/qemu/q-irq.c
+++ b/arch/mips/qemu/q-irq.c
@@ -1,4 +1,5 @@
 #include <linux/init.h>
+#include <linux/interrupt.h>
 #include <linux/linkage.h>
 
 #include <asm/i8259.h>