[PATCH] i386: Handle non existing APICs without panicing

[description from AK]

This fixes booting in APIC mode on some ACER laptops. x86-64
did a similar change some time ago.

See http://bugzilla.kernel.org/show_bug.cgi?id=4700 for details

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index f2dd218..235822b 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -2566,8 +2566,10 @@
 		spin_unlock_irqrestore(&ioapic_lock, flags);
 
 		/* Sanity check */
-		if (reg_00.bits.ID != apic_id)
-			panic("IOAPIC[%d]: Unable change apic_id!\n", ioapic);
+		if (reg_00.bits.ID != apic_id) {
+			printk("IOAPIC[%d]: Unable to change apic_id!\n", ioapic);
+			return -1;
+		}
 	}
 
 	apic_printk(APIC_VERBOSE, KERN_INFO