xtensa: add support for KC705

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
WIP: xtensa: update FSF variant

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
WIP: xtensa: xtfpga: add CY7C67300 USB controller support

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
WIP: xtensa: add i2c host controller to xtfpga dts

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>