platform/x86: dell-smbios: Auto-select as needed

Dell-smbios is a helper module, it serves no purpose on its own, so
do not present it as an option to the user. Instead, select it
automatically whenever a driver which needs it is selected.

Also select DCDBAS as needed, instead of depending on it, so that
the Dell driver options are always visible.

As a clean-up, I removed the "default n" statements as they are not
needed (n is the default default.)

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Michał Kępień <kernel@kempniu.pl>
Cc: Pali Rohár <pali.rohar@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>