platform/x86: pcengines-apuv2: Make two symbols static

Fix sparse warnings:

drivers/platform/x86/pcengines-apuv2.c:80:27: warning: symbol 'gpios_led_table' was not declared. Should it be static?
drivers/platform/x86/pcengines-apuv2.c:113:27: warning: symbol 'gpios_key_table' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-By: Enrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>