x86: add driver for Lenovo ideapad S10-3T rotate button (v2)

Provided by Javier S. Pedro.

(v2)
Changes due to following commits:
79a56f4 "platform/x86: wmi: Remove wmi_get_event_data()"
e04e2b7 "platform/x86: wmi: Pass event data directly to legacy notify handlers"

Fixes the following building errors:

./kernel/drivers/platform/x86/lsrot.c:134:11: error: implicit declaration of function 'wmi_get_event_data' is invalid in C9
9 [-Werror,-Wimplicit-function-declaration]
        status = wmi_get_event_data(value, &response);
                 ^
  CC [M]  drivers/staging/rtl8723bs/hal/HalHWImg8723B_MAC.o
./kernel/drivers/platform/x86/lsrot.c:206:38: error: incompatible function pointer types passing 'void (u32, void *)' (aka
'void (unsigned int, void *)') to parameter of type 'wmi_notify_handler' (aka 'void (*)(union acpi_object *, void *)') [-Werror,-Wincompatible-func
tion-pointer-types]
                                            event_handler, NULL);
                                            ^~~~~~~~~~~~~
./kernel/include/linux/acpi.h:404:25: note: passing argument to parameter 'handler' here
                                        wmi_notify_handler handler, void *data);
                                                           ^
2 errors generated.

Author: maurossi

drivers/platform/x86/lsrot.c

@@ -125,20 +125,8 @@ static int set_ap_bit(int ap, bool enabled)
 	return 0;
 }
 
-static void event_handler(u32 value, void *context)
+static void event_handler(union acpi_object *obj, void *context)
 {
-	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
-	union acpi_object *obj;
-	acpi_status status;
-
-	status = wmi_get_event_data(value, &response);
-	if (ACPI_FAILURE(status)) {
-		printk(KERN_WARNING "%s: bad event\n", DRIVER_NAME);
-		return;
-	}
-
-	obj = (union acpi_object *)response.pointer;
-
 	if (obj && obj->type == ACPI_TYPE_BUFFER && obj->buffer.length == 0x40) {
 		u8 * data = (u8*) obj->buffer.pointer;
 		switch (EVID(data)) {
@@ -159,8 +147,6 @@ static void event_handler(u32 value, void *context)
 	} else {
 		printk(KERN_WARNING "%s: bad event\n", DRIVER_NAME);
 	}
-
-	kfree(obj);
 }
 
 static int __init lsrot_init_module (void)