firmware: use noinline_for_stack

The comment above fw_file_size() suggests it is noinline for stack size
reasons. Use noinline_for_stack to make this more clear.

Cc: Ming Lei <ming.lei@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Acked-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/base/firmware_class.c

@@ -275,7 +275,7 @@ static const char *fw_path[] = {
 };
 
 /* Don't inline this: 'struct kstat' is biggish */
-static noinline long fw_file_size(struct file *file)
+static noinline_for_stack long fw_file_size(struct file *file)
 {
 	struct kstat st;
 	if (vfs_getattr(file->f_path.mnt, file->f_path.dentry, &st))