sh: Convert ins[bwl]/outs[bwl] macros to inline functions

Macro ins[bwl]/outs[bwl] are just calling BUG(), but that results in
unused variable warnings all over the place.
This patch convert macro to inline to avoid warning

We will get this kind of warning without this patch

	${LINUX}/drivers/iio/adc/ad7606_par.c:21:23: \
	  warning: unused variable 'st' [-Wunused-variable]
	struct ad7606_state *st = iio_priv(indio_dev);
	^~

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Rich Felker <dalias@libc.org>