HID: i2c-hid: acpi: Move GUID out of function and described it

Move static GUID variable out of the function and add a comment
how it looks like in the human readable representation.

While at it, include uuid.h since the guid_t type is defined in it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/i2c-hid/i2c-hid-acpi.c

@@ -25,6 +25,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pm.h>
+#include <linux/uuid.h>
 
 #include "i2c-hid.h"
 
@@ -42,11 +43,13 @@ static const struct acpi_device_id i2c_hid_acpi_blacklist[] = {
 	{ },
 };
 
-static int i2c_hid_acpi_get_descriptor(struct acpi_device *adev)
-{
-	static guid_t i2c_hid_guid =
+/* HID I²C Device: 3cdff6f7-4267-4555-ad05-b30a3d8938de */
+static guid_t i2c_hid_guid =
 	GUID_INIT(0x3CDFF6F7, 0x4267, 0x4555,
 		  0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE);
+
+static int i2c_hid_acpi_get_descriptor(struct acpi_device *adev)
+{
 	acpi_handle handle = acpi_device_handle(adev);
 	union acpi_object *obj;
 	u16 hid_descriptor_address;