dt-bindings: pinctrl: xilinx: Rename *gpio to *gpio-grp

dt-bindings: pinctrl: xilinx: Rename *gpio to *gpio-grp

Anything ending with gpio/gpios is taken as gpio phande/description which
is reported as the issue coming from gpio-consumer.yaml schema.
That's why rename the gpio suffix to gpio-grp to avoid name collision.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/2e3a1f1f57cf929bd05115bc081e6d01d5a53443.1702996859.git.michal.simek@amd.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>