reset: Supply *_shared variant calls when using of_* API

Consumers need to be able to specify whether they are requesting an
'exclusive' or 'shared' reset line no matter which API (of_*, devm_*,
etc) they are using.  This change allows users of the of_* API in
particular to specify that their request is for a 'shared' line.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>