reset: hisilicon: Add hi6220 media subsystem reset support

Add hi6220 media subsystem reset controller.

Signed-off-by: Chen Feng <puck.chen@hisilicon.com>
Signed-off-by: Xia Qing <saberlily.xia@hisilicon.com>
Signed-off-by: Xinliang Liu <xinliang.liu@linaro.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>