macintosh/ams: mark ams_init() static

This is the module init function, which by definition is used only
locally, so mark it static to avoid a warning:

drivers/macintosh/ams/ams-core.c:179:12: error: no previous prototype for 'ams_init' [-Werror=missing-prototypes]

Signed-off-by: Arnd Bergmann <[e-mail]>
Reviewed-by: Christophe Leroy <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://msgid.link/[e-mail]

drivers/macintosh/ams/ams-core.c

···
 	return result;
 }
 
-int __init ams_init(void)
+static int __init ams_init(void)
 {
 	struct device_node *np;