zephyr: Add default mapping for remote I2C ports
zephyr: Add default mapping for remote I2C ports

For TCPC firmware updates, the host first queries the I2C port from the
EC and passes this back during I2C passthrough operations. Default to a
1:1 mapping of the remote port to local port, if the devicetree doesn't
explicitly set the remote-port property.

BUG=b:197153501
BRANCH=none
TEST=Boot zephyr with AUX firmware updates enabled in depthcharge,
verify the TCPC firmware is updated.

Signed-off-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>
Change-Id: Ie45d302044e94c0325b36cc41c528fc0ca858384
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3158974
Reviewed-by: Jack Rosenthal <d3f605bef1867f59845d4ce6e4f83b8dc9e4e0ae@chromium.org>
Reviewed-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@google.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec