input: i8042 - add runtime check in x86's i8042_platform_init

Then it will first check x86_platforms's i8042 detection result,
then go on with normal probe.

Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <4c34dd482753bb8f1@agluck-desktop.sc.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

drivers/input/serio/i8042-x86ia64io.h

@@ -7,6 +7,10 @@
  * the Free Software Foundation.
  */
 
+#ifdef CONFIG_X86
+#include <asm/x86_init.h>
+#endif
+
 /*
  * Names.
  */
@@ -840,6 +844,12 @@ static int __init i8042_platform_init(void)
 {
 	int retval;
 
+#ifdef CONFIG_X86
+	/* Just return if pre-detection shows no i8042 controller exist */
+	if (!x86_platform.i8042_detect())
+		return -ENODEV;
+#endif
+
 /*
  * On ix86 platforms touching the i8042 data register region can do really
  * bad things. Because of this the region is always reserved on ix86 boxes.