dt-bindings: xilinx: Switch xilinx.com emails to amd.com

@xilinx.com is still working but better to switch to new amd.com after
AMD/Xilinx acquisition.

Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Acked-by: Damien Le Moal <dlemoal@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/f5b2bd1e78407e4128fc8f0b5874ba723e710a88.1684245058.git.michal.simek@amd.com