ide/legacy/gayle.c: add MODULE_LICENSE

Now that it can be built modular it needs a MODULE_LICENSE.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/legacy/gayle.c

@@ -195,3 +195,5 @@ static int __init gayle_init(void)
 }
 
 module_init(gayle_init);
+
+MODULE_LICENSE("GPL");