ACPI: processor: fix acpi_get_cpuid for UP processor

For UP processor, it is likely that no _MAT method or MADT table defined.
So currently acpi_get_cpuid(...) always return -1 for UP processor.
This is wrong. It should return valid value for CPU0.

In the other hand, BIOS may define multiple CPU handles even for UP
processor, for example

Scope (_PR)
{
Processor (CPU0, 0x00, 0x00000410, 0x06) {}
Processor (CPU1, 0x01, 0x00000410, 0x06) {}
Processor (CPU2, 0x02, 0x00000410, 0x06) {}
Processor (CPU3, 0x03, 0x00000410, 0x06) {}
}

We should only return valid value for CPU0's acpi handle.
And return invalid value for others.

http://marc.info/?t=132329819900003&r=1&w=2

Cc: [e-mail]
Reported-and-tested-by: [e-mail]
Signed-off-by: Lin Ming <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/acpi/processor_core.c

···
 	apic_id = map_mat_entry(handle, type, acpi_id);
 	if (apic_id == -1)
 		apic_id = map_madt_entry(type, acpi_id);
-	if (apic_id == -1)
-		return apic_id;
+	if (apic_id == -1) {
+		/*
+		 * On UP processor, there is no _MAT or MADT table.
+		 * So above apic_id is always set to -1.
+		 *
+		 * BIOS may define multiple CPU handles even for UP processor.
+		 * For example,
+		 *
+		 * Scope (_PR)
+                 * {
+		 *     Processor (CPU0, 0x00, 0x00000410, 0x06) {}
+		 *     Processor (CPU1, 0x01, 0x00000410, 0x06) {}
+		 *     Processor (CPU2, 0x02, 0x00000410, 0x06) {}
+		 *     Processor (CPU3, 0x03, 0x00000410, 0x06) {}
+		 * }
+		 *
+		 * Ignores apic_id and always return 0 for CPU0's handle.
+		 * Return -1 for other CPU's handle.
+		 */
+		if (acpi_id == 0)
+			return acpi_id;
+		else
+			return apic_id;
+	}
 
 #ifdef CONFIG_SMP
 	for_each_possible_cpu(i) {