mux: include compiler.h from mux/consumer.h

Required for __must_check.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: NPeter Rosin <peda@axentia.se>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/mux/consumer.h

@@ -13,6 +13,8 @@
 #ifndef _LINUX_MUX_CONSUMER_H
 #define _LINUX_MUX_CONSUMER_H
 
+#include <linux/compiler.h>
+
 struct device;
 struct mux_control;