UPSTREAM: drivers: gpio: Add support for PCAL6408A I/O expander

Add GPIO driver and devicetree binding for the PCAL6408A 8-bit I2C-bus
I/O expander.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
(cherry picked from commit 1314ab54045d2ea143e115c83900ede8273118a3)

TEST=none
BUG=none

Change-Id: I605f9db8b96f244f883016f483694bbcc3a20c46
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/zephyr/+/2882658
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Reviewed-by: Denis Brockus <dbrockus@chromium.org>
Tested-by: Denis Brockus <dbrockus@chromium.org>
Commit-Queue: Denis Brockus <dbrockus@chromium.org>
5 files changed