ps2: avoid repeated header file includes

Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

hw/ps2.h

@@ -1,3 +1,30 @@
+/*
+ * QEMU PS/2 keyboard/mouse emulation
+ *
+ * Copyright (C) 2003 Fabrice Bellard
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef HW_PS2_H
+#define HW_PS2_H
+
 /* ps2.c */
 void *ps2_kbd_init(void (*update_irq)(void *, int), void *update_arg);
 void *ps2_mouse_init(void (*update_irq)(void *, int), void *update_arg);
@@ -7,3 +34,5 @@ uint32_t ps2_read_data(void *);
 void ps2_queue(void *, int b);
 void ps2_keyboard_set_translation(void *opaque, int mode);
 void ps2_mouse_fake_event(void *opaque);
+
+#endif /* !HW_PS2_H */