platform/x86: Remove "default n" entries

Linus already once did that for PDx86, don't repeat our mistakes.
TL;DR: 'n' *is* the default 'default'.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210618125516.53510-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>