x86/Kconfig: Simplify X86_UP_APIC handling

x86/Kconfig: Simplify X86_UP_APIC handling

We don't really need a helper symbol for that. For one, it's
pointlessly getting set to Y for all configurations (even 64-bit
ones). And then the purpose can be fulfilled by suitably
adjusting X86_UP_APIC: Hide its prompt when PCI_MSI, and default
it to PCI_MSI.

Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/54D39AFC020000780005D684@mail.emea.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>