[ACPI] Don't enable LAPIC when the BIOS disabled it.

Doing so apparently breaks every Dell on Earth.
http://bugzilla.kernel.org/show_bug.cgi?id=3238

arch/i386/kernel/apic.c

@@ -690,22 +690,8 @@ static int __init detect_init_APIC (void)
 		goto no_apic;
 	}
 
-	if (!cpu_has_apic) {
-		/*
-		 * Some BIOSes disable the local APIC in the
-		 * APIC_BASE MSR. This can only be done in
-		 * software for Intel P6 and AMD K7 (Model > 1).
-		 */
-		rdmsr(MSR_IA32_APICBASE, l, h);
-		if (!(l & MSR_IA32_APICBASE_ENABLE)) {
-			apic_printk(APIC_VERBOSE, "Local APIC disabled "
-					"by BIOS -- reenabling.\n");
-			l &= ~MSR_IA32_APICBASE_BASE;
-			l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
-			wrmsr(MSR_IA32_APICBASE, l, h);
-			enabled_via_apicbase = 1;
-		}
-	}
+	if (!cpu_has_apic)
+		goto no_apic;
 	/*
 	 * The APIC feature bit should now be enabled
 	 * in `cpuid'