Add interrupt clear register define for further chip support.

Signed-off-by: Tommy Haung <tommy_huang@aspeedtech.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302024930.18758-4-tommy_huang@aspeedtech.com