gpio: mcp230xx: Introduce new driver

Introduce driver for I2C based MCP230xx GPIO chips, which are
quite common and already well supported by the Linux kernel.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
3 files changed