platform/x86: p2sb: Move out of X86_PLATFORM_DEVICES dependency

The P2SB library is used for various drivers, including server
platforms. That's why the dependency on X86_PLATFORM_DEVICES
seems superfluous.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220718145328.14374-1-andriy.shevchenko@linux.intel.com


Signed-off-by: Hans de Goede <hdegoede@redhat.com>