ACPI / IPMI: Cleanup some inclusion codes

This (trivial) patch:
 1. Deletes several useless header inclusions.
 2. Kernel codes should always include <linux/acpi.h> instead of
    <acpi/acpi_bus.h> or <acpi/acpi_drivers.h> where many conditional
    declarations are handled.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reviewed-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_ipmi.c

@@ -24,22 +24,9 @@
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */
 
-#include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/init.h>
-#include <linux/types.h>
-#include <linux/delay.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/interrupt.h>
-#include <linux/list.h>
-#include <linux/spinlock.h>
-#include <linux/io.h>
-#include <acpi/acpi_bus.h>
-#include <acpi/acpi_drivers.h>
+#include <linux/acpi.h>
 #include <linux/ipmi.h>
-#include <linux/device.h>
-#include <linux/pnp.h>
 #include <linux/spinlock.h>
 
 MODULE_AUTHOR("Zhao Yakui");