platform/x86: Kconfig: Fix dell-laptop dependency chain.

As reported by Randy Dunlap:
>> WARNING: unmet direct dependencies detected for DELL_SMBIOS
>>   Depends on [m]: X86 [=y] && X86_PLATFORM_DEVICES [=y]
>>	&& (DCDBAS [=m] ||
>> DCDBAS [=m]=n) && (ACPI_WMI [=n] || ACPI_WMI [=n]=n)
>>   Selected by [y]:
>>   - DELL_LAPTOP [=y] && X86 [=y] && X86_PLATFORM_DEVICES [=y]
>> && DMI [=y]
>> && BACKLIGHT_CLASS_DEVICE [=y] && (ACPI_VIDEO [=n] ||
>>	ACPI_VIDEO [=n]=n)
>> && (RFKILL [=n] || RFKILL [=n]=n) && SERIO_I8042 [=y]
>>

Right now it's possible to set dell laptop to compile in but this
causes dell-smbios to compile in which breaks if dcdbas is a module.

Dell laptop shouldn't select dell-smbios anymore, but depend on it.

Fixes: 32d7b19b

 (platform/x86: dell-smbios: Resolve dependency error on DCDBAS)
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Cc: stable@vger.kernel.org
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>