x86, apic: Slim down stack usage in early_init_lapic_mapping()

As far as I see there is no external poking of mp_lapic_addr in
this procedure which could lead to unpredited changes and
require local storage unit for it. Lets use it plain forward.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20090826171324.GC4548@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/apic/apic.c

@@ -1562,20 +1562,16 @@ static int __init detect_init_APIC(void)
 #ifdef CONFIG_X86_64
 void __init early_init_lapic_mapping(void)
 {
-	unsigned long phys_addr;
-
 	/*
 	 * If no local APIC can be found then go out
 	 * : it means there is no mpatable and MADT
 	 */
 	if (!smp_found_config)
 		return;
 
-	phys_addr = mp_lapic_addr;
-
-	set_fixmap_nocache(FIX_APIC_BASE, phys_addr);
+	set_fixmap_nocache(FIX_APIC_BASE, mp_lapic_addr);
 	apic_printk(APIC_VERBOSE, "mapped APIC to %16lx (%16lx)\n",
-		    APIC_BASE, phys_addr);
+		    APIC_BASE, mp_lapic_addr);
 
 	/*
 	 * Fetch the APIC ID of the BSP in case we have a