[PATCH] Fix x86-64 boot problem

From: Andi Kleen <ak@muc.de>

Fix a bug introduced with the last merge that prevented booting with
CONFIG_DEBUG_INFO on on x86-64.  It would corrupt registers in interrupts.
This has hit a few people, so I would consider it as a critical fix.

arch/x86_64/kernel/entry.S

@@ -436,7 +436,7 @@ ret_from_intr:
 	popq  %rdi
 	cli	
 	subl $1,%gs:pda_irqcount
-#ifdef CONFIG_KGDB
+#ifdef CONFIG_DEBUG_INFO
 	movq RBP(%rdi),%rbp
 #endif
 	leaq ARGOFFSET(%rdi),%rsp