i2c: pca-platform: Fix GPIO lookup code

The devm_gpiod_request_gpiod() call will add "-gpios" to
any passed connection ID before looking it up.

I do not think the reset GPIO on this platform is named
"reset-gpios-gpios" but rather "reset-gpios" in the device
tree, so fix this up so that we get a proper reset GPIO
handle.

Also drop the inclusion of the legacy GPIO header.

Fixes: 0e8ce93b ("i2c: pca-platform: add devicetree awareness")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>